Introduction

Feeding diets with a high insoluble:soluble fibre ratio has been suggested as a strategy to improve gut function in newly weaned piglets (Molist et al., 2014).

Fermentation of DDGS, via soaking in water for an extended period with added fibre-degrading enzymes and microbial inoculants, can be used to target the soluble fibre portion, increasing the insoluble:soluble fibre ratio.

The resulting product is a more valuable feed ingredient for young pigs. Fermentation would also convert energy present in soluble fibre to short chain and organic fatty acids, improving energy availability and thus feed efficiency.

Control and stability of the fermentation are crucial for generating a consistent product. A preliminary study was conducted to identify microbial inoculants capable of controlling the fermentation of DDGS when combined with fibre-degrading enzymes and to determine the optimal feeding window.

A growth trial was then carried out using piglets weaned at 20 days of age and fed liquid corn and soybean meal based diets combined with DDGS to determine the impact of fermenting DDGS on growth performance of weanling piglets. Liquid feeding unfermented DDGS supplemented with the microbial inoculants and fibre-degrading enzymes served as the control.

Materials and Methods

DDGS-containing diets were fed to newly weaned pigs (eight pens per diet, 14 pigs per pen).

The two treatments, fermented DDGS (ferDDGS) and unfermented DDGS (uferDDGS) were formulated as identical corn and soybean meal based diets to meet or exceed NRC (2012) requirements for three phases:

• Phase I (7.5 per cent DDGS, week 1 post-weaning)
• Phase II (16.25 per cent DDGS, weeks 2 to 3 post-weaning), and
• Phase III (25 per cent DDGS, weeks 4 to 6 post-weaning).

ferDDGS consisted of DDGS (Greenfield Ethanol), which was fermented in 39±3°C water (14 per cent dry matter) with β-glucanase and xylanase; (67.2 and 51.4IU per gram of DDGS respectively; AB Vista) and the silage inoculant Biotal Plus (360,000CFU Pediocoocus pentosaceus 12455 and Propionibacterium jensenii 30081 per g of DDGS with 0.04IU β-glucanase, 0.02IU galactomannanase, and 0.03IU xylanase per gram of DDGS; Lallemand).

ferDDGS was fed between one and seven days after the start of fermentation and mixed with the remaining dry diet components and water (25 to 26 per cent dry matter) just prior to liquid feeding.

uferDDGS consisted of the complete dry diet, enzymes and inoculant (identical inclusion levels as ferDDGS) added to water immediately prior to liquid feeding (25 to 26 per cent dry matter).

As initial bodyweight (BWi) was variable (Table 1) pigs were separated into two rooms according to a heavy BWi (HBWi, 7.6±0.8kg) or light BWi (LBWi, 5.8±0.6kg; n=4 per room).

Per-pen dry matter intake (DMI) and individual pig bodyweights were determined each week for calculating average daily bodyweight gain (ADG) and gain:feed ratio (G:F).

To ensure all pigs ended the trial at a similar bodyweight, LBWi pigs were fed Phase III diets for an additional week, subsequently included in Phase III growth analysis for LBWi pigs.

Results

Despite efforts towards stabilising fermentations, ferDDGS quality was found to be variable between batches with occasional high acetic acid levels (ferDDGS; n=9: 42.6±17.4mM lactic acid; 55.3±37.1mM acetic acid, pH4.8±0.4; uferDDGS [n=3]: 17.6±1.4mM lactic acid; 3.9±0.7 mM acetic acid pH 5.6±0.3).

As there was a significant (P<0.05) interaction between BWi and treatment, growth data was separated according to HBWi and LBWi.

Within the HBWi pigs, average daily gain and bodyweight were higher (P<0.05) in pigs fed uferDDGS in Phase II but not I or III (P>0.10) while dry matter intake was not impacted, resulting in greater gain:feed ratio (P<0.05) in Phase II (Table 1).

Within LBWi pigs, average daily gain and dry matter intake were improved (P<0.05) in pigs fed ferDDGS in Phase III without impacting gain:feed ratio (P>0.10). Bodyweights were higher in usDDGS pigs in Phase II (P<0.05) but no other parameter was impacted (P>0.10; Table 1).

Discussion

Particularly low lactic acid and high acetic acid levels in a particular batch of fermented DDGS are most likely the cause of poor comparative performance during Phase II for HBWi pigs fed ferDDGS.

The lesser impact on LBWi pigs fed ferDDGS is of interest, and is perhaps due to lower overall intake of both diets by LBWi pigs during this time and poorer average daily gain than HBWi pigs.

In spite of unforeseen variability in quality of fermented DDGS batches, ferDDGS was found to improve growth performance late in the nursery period, when dry matter intake begins to increase dramatically, with a distinct benefit to LBWi pigs.

This observation may be due to a lesser ability of LBWi pigs to utilise soluble fibre components of DDGS and thus benefiting more from fermenting ferDDGS.

In addition, pigs potentially compromised by light bodyweight at weaning may benefit more from dietary strategies that affect gut development.

Future work will focus on analysing the impact of the diets on gut development parameters using data collected during the trial to determine mode of action.

Acknowledgments: Funding was provided by OMAFRA, NSERC, Swine Innovation Pork and industrial partners of the swine liquid feeding association (www.slfa.ca).

References

• Molist, F., van Oostrum, M., Pérez, J.F., Mateos, G.G., Nyachoti, C.M. and van der Aar, P J. 2014. Relevance of functional properties of dietary fiber in diets for weanling pigs. Animal Feed Science and Technology. 189:1-10.

Reference

Wiseman M., D. Wey and C.F.M. de Lange. 2015. Feeding of fermented DDGS in a liquid feed system to weanling pigs: Improving growth performance using fibre manipulation with enzymes and microbial inoculants. Proceedings of 34th Annual Centralia Swine Research Update. 28 January 2015. I6-I7.

Further Reading

You can view other papers from the Centralia 2015 Update by clicking here.

May 2015