Cereal grains such as corn and barley serve as sources of energy in swine diets because of their high starch content. However, these feedstuffs, like most other feedstuffs of plant origin, contain fiber and phytate, which reduces dietary nutrient utilization. Furthermore, in cereal grains, starch is surrounded with proteins, which reduces the availability of the starch to starch-digesting enzymes.
Supplementation of the cereal grain-based diets for pigs with enzymes that target fiber, phytate and protein in these diets can potentially improve nutrient utilization. Weaned pigs have poorly developed digestive systems compared to growing-finishing pigs, and would thus potentially benefit more from dietary supplementation of the fore-mentioned enzymes than growing-finishing pigs.
Recent research at South Dakota State University looked at the effect of supplementing corn-barley-based diets for nursery pigs with multi-enzyme supplements on growth performance and nutrient digestibility. In this study, growth performance included average daily gain, average daily feed intake and gain-to-feed ratio; whereas nutrient digestibility included apparent total tract digestibility of gross energy, crude protein and fat.
A total of 132 pigs (with average initial body weight of 7.23 kilograms) that had been weaned at 21 days of age and fed a drug-free nursery diet for seven days were housed in 33 pens of four barrows or gilts, blocked by body weight and gender, and fed three experimental diets at 11 pens per diet. The diets were corn-barley-based diet without or with multi-enzyme A or B (Table 1). Multi-enzyme A supplied 4,000 U of xylanase, 150 U of β-glucanase, 3,500 U of protease and 1,500 U of amylase per kilogram of diet. Multi-enzyme B was the same as multi-enzyme A except that it supplied amylase at 150 U per kilogram, and that its source of amylase was different from that of multi-enzyme A.
All diets contained phytase at 1,000 U per kilogram. The diets were fed for 35 days in two phases; Phase 1 for the first 14 days and Phase 2 for the last 21 days of the trial. Fecal samples were collected from each pen during the last two days of the trial to determine apparent total tract digestibility of nutrients.
Multi-enzyme A or B supplementation increased average daily gain for Phase 1 (Table 2). Multi-enzyme supplemented diets also tended to increase average daily gain and average daily feed intake for Phase 2. For the overall study period, average daily gain and average daily feed intake were increased when pigs were fed a diet with multi-enzyme B by 17.8 and 14.3%, respectively. Multi-enzyme A supplementation increased overall average daily gain and average daily feed intake by 9.43 and 9.42%, respectively. Gain-to-feed ratio was not affected by the multi-enzyme supplementation. Multi-enzyme A and multi-enzyme B supplementation increased the apparent total tract digestibility of fat by 20.0 and 23.7%, respectively. Apparent total tract digestibility of gross energy and crude was unaffected by the multi-enzyme supplementation.
In summary, the results show that multi-enzyme supplementation improved growth performance and nutrient digestibility. Thus, the multi-enzyme products fed in the current study could be used to improve nutrient utilization of corn-barley-based diets for nursery pigs.