Protease Inclusion Improves Growth Performance of Nursery Pigs Consuming Lysine-Deficient Diets

Swine diets are normally digested at about 85% efficacy and dietary proteases may be used to increase the efficiency of protein digestion and reduce cost. In addition, fermentation of undigested protein increases hindgut pH making the environment more favorable for the proliferation of opportunistic pathogens.

Pigs (337 × C-22, PIC, Hendersonville, TN) weaned at 21 days (d) of age were housed (22 pigs per pen, half barrows and half gilts) in a commercial research facility. On d 21 after weaning, pigs were randomly assigned to 3 levels (1.25, 1.15, and 1.05%) of standardized ileal digestible (SID) lysine (Lys) and 2 levels (0 or 500 ppm) of protease (Cibenza® DP100). Corn-soybean meal based diets were formulated to meet or exceed all nutrient recommendations with the exception of SID Lys and were fed for 14 d. Body weight (BW) and feed intake were determined at d 21 and 35 d post-weaning. A Complete Randomized Design with 7 replicate pens per treatment was used and data were analyzed proc mixed (SAS® Institute, Gary, NC).

Lys SID was calculated as 90% of total Lys. Total analyzed Lys was 1.315% for both 1.25% and 1.15% SID Lys treatments and 1.125% for the 1.05% SID Lys treatment. Thus, 1.25 and 1.15 Treatments were combined and results were re-analyzed as a factorial with 2 SID Lys levels (1.18 and 1.01% SID Lys) and 2 protease levels. Reducing dietary SID Lys decreased (P < 0.001) final BW, average daily weight gain, and Gain:Feed ratio but had no impact (P = 0.23) on feed intake. Protease supplementation increased (P = 0.02) final BW, improved (P = 0.10) Gain:Feed ratio, tended (P = 0.12) to increased weight gain, and had no effect (P = 0.44) on feed intake.

Dietary supplementation of protease can overcome a partial deficiency of SID Lys in a corn-soybean meal based diet.

Dietary protease supplementation may be used to increase SID Lys digestibility coefficients in formulation to account for a higher Lys digestibility.

Keywords: Enzyme, lysine, deficiency.