Effects of beta-mannanase addition to corn-soybean meal diets on growth performance, carcass traits, and nutrient digestibility of weanling and growing-finishing pigs.

Four experiments were conducted to determine the effects of adding a beta-mannanase preparation (Hemicell, ChemGen, Gaithersburg, MD) to corn-soybean meal-based diets on growth performance and nutrient digestibility of weanling and growing-finishing pigs. In Exp. 1, 156 weanling pigs (20 d, 6.27 kg BW) were allotted to four dietary treatments in a randomized complete block design. Treatments were a factorial arrangement of diet complexity (complex vs simple) and addition of 3-mannanase preparation (0 vs 0.05%). Pigs were fed in three dietary phases (Phase 1, d 0 to 14; Phase 2, d 14 to 28; and Phase 3, d 28 to 42). Pigs fed complex diets gained faster and were more efficient (P < 0.05) during Phase 1 compared with pigs fed simple diets. Overall, gain:feed ratio (G:F) tended to be improved (P < 0.10) for pigs fed complex diets and it was improved (P < 0.01) for those fed diets with beta-mannanase. In Exp. 2, 117 pigs (44 d, 13.62 kg BW) were allotted randomly to three dietary treatments. Dietary treatments were 1) a corn-soybean meal-based control, 2) the control diet with soybean oil added to increase metabolizable energy (ME) by 100 kcal/kg, and 3) the control diet with 0.05% beta-mannanase preparation. Beta-mannanase or soybean oil improved (P < 0.05) G:F compared with pigs fed the control diet. In Exp. 3, 60 pigs (22.5 kg BW) were allotted randomly to the three dietary treatments used in Exp. 2. Dietary treatments were fed in three phases (23 to 53 kg, 53 to 82 kg, and 82 to 109 kg with 0.95, 0.80, and 0.65% lysine, respectively). Overall, the addition of soybean oil tended to improve G:F (P < 0.10) compared with that of pigs fed the control diet, and G:F was similar (P > 0.54) for pigs fed diets with soybean oil or beta-mannanase. Also, addition of beta-mannanase increased ADG (P < 0.05) compared with that of pigs fed the control or soybean oil diets. There were no differences (P > or = 0.10) in longissimus muscle area or backfat; however, on a fat-free basis, pigs fed the diet with beta-mannanase had greater (P < 0.05) lean gain than pigs fed the control or soybean oil diets. In Exp. 4, 12 barrows (93 kg BW) were allotted randomly to one of the three dietary treatments used in Exp. 3. Addition of 3-mannanase had no effect (P > 0.10) on energy, nitrogen, phosphorus, or dry matter digestibility. These results suggest that beta-mannanase may improve growth performance in weanling and growing-finishing pigs but has minimal effects on nutrient digestibility.

Effects of beta-mannanase in corn-soybean meal diets on laying hen performance.

Recently, a patented enzyme product (beta-Mannanase, Hemicell) has been shown to improve feed conversion in corn-soybean diets fed to broilers and swine. The mechanism of beta-Mannanase is to degrade beta-mannan, which is an antinutritional factor existing in many legumes, including soybean and canola meals. The objective of this study was to determine whether or not performance can be improved by including beta-Mannanase in diets of commercial laying hens, 18 through 66 wk of age. A 2 x 2 x 2 factorial arrangement of treatments was employed. There were two energy sequences of 2,926-2,907-2,885 and 2,827-2,808-2,786 kcal ME/kg, which changed at 33 and 43 wk of age respectively; two dietary enzyme levels (0 and 110 units/g); and two Hy-Line strains (W36 and W77). Hen-day production, hen-housed production, BW, feed intake, mortality, egg weight, and specific gravity data were collected biweekly. Data were analyzed in four cycles (each with six 2-wk periods) and also for the whole experiment. beta-Mannanase increased egg weight from 51.4 to 51.7 g/egg (P < 0.05) in the first 12-wk cycle. This effect was consistent across energy levels. beta-Mannanase significantly improved hen-day and hen-housed production after the first cycle. Hen-day production of the beta-Mannanase group was 0.70, 1.07, and 1.5% greater than the control for cycles two, three, and four, respectively (P < 0.01). After 30 wk of age, average hen-day production of hens fed the low-energy diets with beta-Mannanase was similar or superior to that of hens fed the high-energy diets without the enzyme. The study indicates that beta-Mannanase is capable of increasing egg weight in commercial layers at early stages of production, and increasing egg production, particularly delaying the postpeak decline in productivity.