Evaluation of hemicell® on growth performance of late nursery pigs

A total of 276 pigs (initially 21.9 lb) was used to determine the effects of added HemicellÂ® on growth performance. HemicellÂ® is a patented fermentation product of Bacillus lentus. The active ingredient in the fermentation product is Î2-mannanase. However, other enzymes such as amylase, xylanase, cellulases, and Î±-galactosidase also are present. It is claimed that HemicellÂ® degrades Î2-mannan in feed, thus, removing its effects as an antinutritive factor in swine diets. Dietary treatments were arranged as a 2 x 3 factorial, with or without 0.05% HemicellÂ®, in diets with 3 levels of energy density (1,388, 1,488, 1,588 ME, kcal/lb). The 100 kcal increments were achieved by the addition of wheat bran or soy oil to a corn-soybean meal based diet. The addition of HemicellÂ® to the diets, regardless of energy level, did not lead to an improvement in growth performance in these late nursery pigs. Increasing energy density of the diet, however, resulted in an improved ADG and F/G.; Swine Day, 2003, Kansas State University, Manhattan, KS, 2003


Introduction
A variety of non-starch polysaccharides (NSP) are present in the cell wall structure of many feedstuffs.These NSPs have been shown to diminish growth performance and inhibit nutrient absorption in swine.One class of NSPs are commonly known as hemicelluloses and found in many ingredients used in swine diets, including soybean meal.Soybean meal can contain up to 22.7% NSP on a dry matter basis.Hemicelluloses in soybean meal, specifically galactomannans, are chemically composed of a d-mannose backbone with attached d-galactose molecules.Monogastrics, including pigs, lack the essential enzyme needed to degrade galactomannans.The enzyme, beta-d-mannanase is commercially available as the patented feed additive Hemicell ® .Recent studies by Oklahoma State University have suggested that β-mannanase may improve growth performance in weanling and grow-finish pigs, but has minimal effect on nutrient digestibility.Other research has observed a trend for improvement in lean gain in grow-finish pigs fed Hemicell ® .Thus, our objective in this study was to determine the effects of Hemicell ® inclusion in the diet on growth performance of late nursery pigs.Three levels of energy density were used in the trial to investigate if Hemicell ® will improve energy utilization.

Procedures
A total of 276 pigs (initial BW of 21.9 lb and 32 ± 2 d of age) were used in a 19-d growth assay.Pigs were blocked by weight and allotted to one of six dietary treatments on d 14 postweaning.There were eight pens per treatment.Six replications consisted of six pigs/pen and two replications consisted of five pigs/pen.Pigs were housed in the KSU nursery facility.Each pen was 4 × 5 ft and contained one self-feeder and one nipple waterer to provide ad libitum access to feed and water.Initial temperature was 90°F for the first 5 d after weaning, and was lowered approximately 3°F each week thereafter.
Experimental diets (Table 1) were fed in meal form and were corn-soybean meal based.The trial was conducted using three different energy levels (low, medium, and high), with and without the addition of Hemicell ® .The control diets contained 1,488 kcal ME/lb.Wheat bran was added to reduce the dietary energy concentration to 1,388 kcal ME/lb, while energy was increased by the use of soy oil to give an energy content of 1,588 kcal ME/lb for the high energy diets (100 kcal increments).Pigs were allotted on d 14 postweaning.Average daily gain, ADFI and F/G were determined by weighing pigs and measuring feed disappearance on d 21, 28, and 33 postweaning.Chemical analyses of the experimental diets for Hemicell ® concentrations was performed by ChemGen Corp.The Hemicell® assay results (mmunits/ton) for the diets with and without added Hemicell ® are shown in Table 2.
Data were analyzed as a 2 × 3 factorial with or without 0.05% Hemicell ® and three levels of energy density (1,388, 1,488, and 1,588 ME, kcal/lb), with pen as the experimental unit.Analysis of variance was performed using the MIXED procedure of SAS.The model included all main effects as well as two-way interactions.Hemicell ® (mmunits/ton).The expected results at the 1 lb/ton inclusion rate is 100.0 with an assay range of 95.0 to 115.0.b These results indicate normal background levels that are typical in untreated samples.

Results and Discussion
From d 0 to 7, there was no interaction observed between Hemicell ® and dietary energy density.Pigs fed diets with added Hemi-cell® performed similarly to those pigs fed diets without Hemicell ® (Table 3).Feed efficiency improved as ME concentration increased from 1,388 to 1,488 Kcal ME, but did not continue to improve in pigs fed diets with 1,588 Kcal ME/lb (quadratic, P<0.05).
From d 7 to 14, there was a tendency for a Hemicell ® × energy interaction for ADFI (P<0.06).Pigs fed diets with added Hemicell ® showed had decreased ADFI as energy density of the diet increased, whereas ADFI of pigs fed diets without Hemicell ® were unaffected by increasing energy density.Average daily gain and F/G was similar for those pigs fed diets with and without Hemicell ® .There was a linear improvement in F/G (P<0.01) as energy density of the diet increased.
From d 14 to 19 of the trial, results were similar to those observed d 0 to 14.There was no Hemicell ® × energy interaction observed.The effect of Hemicell ® was again not shown to be significant (Table 3).A linear increase in ADG and F/G was observed as dietary energy density increased (P<0.01).
Overall, from d 0 to 19, there were no Hemicell ® × energy interactions observed.In addition, no effect of Hemicell ® was observed.Increasing the energy density of the diet improved (quadratic, P<0.05) ADG and F/G.The greatest improvement in performance occurred as dietary energy density was increased from 1,388 to 1,488 ME, kcal/lb.Similarly, ADFI decreased (quadratic, P<0.05) as energy density of the diet increased.
In summary, addition of Hemicell ® did not improve ADG, ADFI, or F/G in this experiment.As the energy density of the diet increased from 1,388 to 1,588 kcal/lb ME, there was a quadratic (P<0.05)improvement in ADG and F/G.The greatest response occurred as dietary energy density increased from 1,388 to 1,488 kcal/lb ME.Increasing energy density of the diet resulted in a reduction in feed intake (quadratic, P<0.05).This trial does not support data from other studies where an improvement in growth performance, due to the addition of Hemicell ® in nursery diets, has been observed.A total of 276 pigs (six replications consisted of six pigs per pen and two replications consisted of five pigs per pen) with an average initial BW of 21.9 lb.Treatment diets were fed from d 0 to 19 of the experiment.b Hemicell ® was added at 0.05% of the diet.

Table 1 . Composition of Experimental Diets
a Hemicell ® replaced sand in each diet to provide the additional dietary treatments.