The Veterinary Feed Directive and concerns about antibiotic-resistant bacteria have changed the way the pig industry utilizes antibiotics in the feed. Gone are antibiotics used at sub-therapeutic levels. Pork producers are now looking at alternative strategies, especially in the diets of newly weaned pigs.
Spray-dried plasma has been a staple feed additive in nursery diets for the last few decades and has been repeatedly shown to improve pig performance. Dried egg additives, produced by hyper-immunizing hens against pathogens harmful to pigs and drying their eggs into a product with concentrated antibodies, are newer to the market.
Iowa State University conducted an experiment to evaluate the effects of spray-dried plasma protein or dried egg protein, with or without antibiotics, on the growth and health of nursery pigs. The 42-day experiment was conducted at a commercial wean-to-finish research facility with 1,230 pigs. There were six dietary treatments arranged as a 3×2 factorial: specialty proteins (none [CON], spray-dried plasma protein [SDPP] or dried egg protein [DEP]) fed without or with in-feed antibiotics. Diets were fed in four phases with the last two being common diets. Antibiotics were included in phases 1-3, and SDPP and DEP were included at 3.0% or 0.20% in phase 1 and 2.0% or 0.10% in phase 2, respectively.
The pigs experienced two health challenges during the experiment. Porcine rotavirus and Salmonella were diagnosed during week two and porcine reproductive and respiratory syndrome virus and influenza were diagnosed during week five. Mortality was 2.0% and morbidity, pigs removed due to illness or injury, was 6.3%. These removal rates were not influenced by diet. However, including SDPP or DEP reduced the number of individual medical treatments compared to the CON diets by 25% (P=0.001).
For the overall nursery period and in the absence of antibiotics, SDPP and DEP improved ADG by 9% and ADFI by 6% compared to CON. When antibiotics were included in the diets, these proteins did not have an effect compared to CON. However, SDPP increased gain by 7% and feed intake by 5% over DEP (P 0.10).
The overall cost of gain was calculated using the cost of experimental diets (prices from mid-2018 at the time of the study) and individual medical treatments; no other costs were considered. Without antibiotics in the diets, the cost of gain for CON and DEP was similar, but SDPP increased cost of gain by 7%. In the presence of antibiotics, SDPP increased the cost of gain by 9% and DEP by 5% compared to CON. Antibiotics tended to decrease the cost of gain by 3% in the CON diet (P=0.064).
Our research showed that specialty proteins positively impacted pig performance in antibiotic-free diets but not when antibiotics were included. However, the proteins benefited pig health by decreasing individual medical treatments regardless of antibiotic use.
As the pork industry continues to decrease its use of antibiotic growth promoters, specialty proteins such as spray-dried plasma or dried egg could be a practical way to help pigs through the transition at weaning. In this example, the DEP appeared to be the more cost-effective option.
Specialty Proteins and Antibiotics in Nursery Pig Diets