Porcine epidemic diarrhea virus (PEDV) can be spread via contaminated feed. Treating PEDV-contaminated feed with formaldehyde has been shown to prevent infection in pigs that consume the feed. However, concerns have been raised about the effect of treatment with formaldehyde on the nutritional value of feedstuffs. Therefore, an experiment was conducted to determine the effects of adding a formaldehyde-based feed disinfectant to the diet on the apparent ileal digestibility (AID) of dry matter, crude protein, and amino acids, and the apparent total tract digestibility (ATTD) of dry matter, gross energy (GE), calcium, and phosphorus in nursery pigs.

Materials and methods

Eight growing pigs with an average initial body weight of 26.8 kg were equipped with a T-cannula at the distal ileum. The pigs were fed two diets based on corn, soybean meal, distillers dried grains with solubles (DDGS), and oats. A proprietary premix (PGF 650 base product) supplied by Kemin Industries, Inc. comprised 32.5% of each diet. For the control diet, the premix was treated with saline; for the experimental diet, the premix was treated with Sal CURB®, a formaldehyde-based feed disinfectant. The diets were identical except for the treatment of the premix. There was an adaptation period of 4 days to the experimental diets. Fecal samples were collected on days 5 and 6 of each period, and ileal digesta were collected on days 6 and 7. Each of the premix products was also sampled at the start of the experiment and at 7, 28, and 49 days to evaluate the impact of Sal CURB on phytase and vitamin stability.

No differences were observed between the control and Sal CURB diets in the apparent ileal digestibility (AID) of dry matter, crude protein, and all amino acids except methionine (Table 1). The AID of methionine was greater (P < 0.05) in the diet treated with Sal CURB than in the control diet.

The apparent total tract digestibility (ATTD) of dry matter and gross energy was the same in the two diets. (Table 2).  The ATTD of calcium and phosphorus was greater (P < 0.05) in the diet treated with Sal CURB than in the control diet.

The PGF 650 premix treated with Sal CURB contained less (P < 0.05) phytase than the control premix on days 0, 7, 28, and 49 (Table 3). However, the digestibility of phosphorus in diets containing Sal CURB indicates that the amount of phytase in those diets was sufficient. Phytase concentration in both the control and treated premixes decreased as storage time increased.

The concentration of most vitamins was the same in the control batch of PGF 650 premix and in the batch treated with Sal CURB (Table 4). The Sal CURB treated premix contained more (P < 0.05) Vitamins B3 and B9 on day 0, more (P < 0.05) Vitamin B1 on day 28, and more (P < 0.05) Vitamins B1, B2, and D3 on day 49 than the control premix.

Key points

• The addition of Sal CURB to swine diets did not affect the digestibility of dry matter, crude protein, amino acids, and gross energy. Digestibility of phosphorus and calcium was greater in diets treated with Sal CURB than in identical diets treated with saline.
• Diets treated with Sal CURB can be stored for at least 49 days without degradation of vitamin content. The phytase in Sal CURB diets degrades over time, but not below adequate levels.
• Sal CURB can be added to swine diets without diminishing the nutritional value of the diets.

Table 1. Apparent ileal digestibility (AID) of dry matter, crude protein, and amino acids (AA) in experimental diets, as-fed basis

Table 2. Apparent total tract digestibility (ATTD) of dry matter, gross energy, calcium, and phosphorus in experimental diets, as-fed basis

Table 3. Effects of Sal CURB on the concentration of phytase in PGF 650 base products

Table 4. Effects of Sal CURB on the concentration of vitamins in PGF 650 base products