In a Norwegian/Dutch/American research collaboration the effects of steam conditioning at low and high temperature, expander conditioning and extruder processing prior to pelleting on growth performance and nutrient digestibility in nursery pigs and broiler chickens was studied.
The aim of the this study was to investigate effects of feed conditioning prior to pelleting and extrusion processing on average daily gain (ADG), average daily feed intake (ADFI), gain to feed (G:F) and coefficient of total tract apparent digestibility (CTTAD) in nursery pigs and broiler chickens.
The mash, based on wheat, fishmeal and soybean meal, was subjected to 4 heat treatments (hydro-thermal processing) giving:
- Diet 1: unconditioned mash as control (mash);
- Diet 2: low-temperature steam conditioning before pelleting (STP47);
- Diet 3: high-temperature steam conditioning before pelleting (STP90);
- Diet 4: expander conditioning before pelleting (EXP); and
- Diet 5: extruder processing (EXT).
Nursery pigs (average body weight of 5.6 kg) were used in a 36-d experiment. Broiler chickens (1-d old, average body weight of 41 g) were used in a 21-d experiment.
Results in pigs
The results showed that hydro-thermal processing improved G:F in nursery pigs compared to the mash. The G:F was also improved for pigs fed Diet 5 compared to Diet 4.
The CTTAD of dry matter was greater in pigs fed the hydro-thermal processed diets compared to the mash, and in pigs fed Diet 2 compared to Diet 3.
The CTTAD of organic matter was improved for pigs fed Diets 2 and 3compared to the Diets 4 and 5, and for Diet 2compared to Diet 3.
The CTTAD of protein and energy was greatest in pigs fed diet 2 compared to Diet 3. Starch digestibility was improved in pigs fed Diet 5 compared to Diet 4.
Results in broilers
The ADFI and ADG were greater for broiler chickens fed Diet 2 and Diet 3 compared to those fed Diet 4 and 5.
Diet 4 improved ADG and ADFI compared to Diet 5. Starch digestibility was greater in broiler chickens fed the hydro-thermal processed diets compared to the mash.
Hydro-thermal processing, in particular extruder processing, improved G:F for nursery pigs due to improved digestibility.
For broiler chickens, all hydro-thermal processing increased starch digestibility, but due to reduced feed intake of the expanded and in particular the extruded diets, only steam conditioning before pelleting improved growth rate and feed utilisation.
Abstracted from: Animal Feed science & Technology (Aug 2011)