The effectiveness of carbohydrase enzymes has been inconsistent in corn-based swine diets, according to C.K. Jones at Kansas State University, however, the increased substrate of non-starch polysaccharides in drought-affected corn may provide an economic model for enzyme inclusion but this has not been evaluated.

In a paper in Journal of Animal Science co-authored by others at Manhattan, Iowa State University and DSM Nutritional Products, Jones explains that they used a total of 360 barrows (PIC 1050 × 337, initially 5.85kg bodyweight) to determine the effects of drought-affected corn inclusion with or without supplementation of commercial carbohydrases on growth performance and nutrient digestibility of nursery pigs.

Initially, 34 corn samples were collected to find representatives of normal and drought-affected corn.

The lot selected to represent the normal corn had a test weight of 719.4kg per cubic metre, 15.0 per cent moisture and 4.2 per cent xylan. The lot selected to represent drought-affected corn had a test weight of 698.8kg per square metre, 14.3 per cent moisture and 4.7 per cent xylan.

After a 10-day acclimatisation period after weaning, nursery pigs were randomly allotted to one of eight dietary treatments in a completely randomised design. Treatments were arranged in a 2×4 factorial with main effects of corn (normal versus drought-affected) and enzyme inclusion (none versus 100mg per kg Enzyme A versus 250mg per kg Enzyme B versus 100mg per kg Enzyme A + 250mg per kg Enzyme B).

Both enzymes were included blends of β-glucanase, cellulose and xylanase (Enzyme A) or hemicellulase and pectinases (Enzyme B).

Pigs were fed treatment diets from days 10 to 35 post weaning in two phases.

Feed and fecal samples were collected on day 30 post-weaning to determine apparent total tract digestibility of nutrients.

The nutrient concentrations of normal and drought-affected corn were similar, which resulted in few treatment or main effects differences of corn type or enzyme inclusion.

No interactions were observed (P>0.10) between corn source and enzyme inclusion.

Overall (days 10 to 35), treatments had no effect on average daily gain or average daily feed intake but enzyme A inclusion tended to improve (P<0.10; 0.74 versus 0.69) gain:feed ratio, which was primarily driven by the improved feed efficiency (0.76 versus 0.72; P<0.05) of pigs fed Enzyme A in Phase 2 (days 10 to 25 post-weaning) and was likely a result of improved xylan utilisation.

Jones and co-authors concluded that drought stress did not alter the non-starch polysaccharide (NSP) concentration of corn beyond xylan concentration, so it was not surprising that enzyme inclusion showed little benefit to nursery pig growth performance.

However, they added, improved feed efficiency of pigs fed diets containing Enzyme A from days 10 to 25 post-weaning warrants further investigation.

Reference

Jones C.K., E.L. Frantz, A.C. Bingham, J.R. Bergstrom, J.M. DeRouchey and J.F. Patience. 2015. Effects of drought-affected corn and nonstarch polysaccharide enzyme inclusion on nursery pig growth performance. Journal of Animal Science. 93:1703-1709.

Further Reading

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April 2015