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A total of 384 purebred Yorkshire pigs were weaned between 19 and 23 d of age at a BW of 5.8±0.45 kg. They were housed in 24 wean-to- finish pens of 16 pigs each (eight barrows and eight gilts, balanced for initial BW and litter mates across treatments). Pens within blocks were randomly assigned one of four HMC-based (High Moisture Corn) dietary treatments for a total of six pens per treatment. Pigs were kept on the experimental treatments until the average block BW exceeded 20 kg, which was a minimum of 6 week. Across three treatments, diets were formulated to vary in P contents (High, Medium, and Low) and the fourth treatment phytase (Phy) represented the Low treatment supplemented with 500 FTU/kg of HMC on a dry matter basis. For the Phy treatment, HMC was steeped with 500FTU/kg DM of phytase. The complete liquid diets were automatically prepared for each pen at each feeding time using liquid feeding system by mixing dry supplements, HMC, and water to achieve a DM to water ratio of 1:2.5. The High, Medium, and Low dietary treatments were achieved by mixing the appropriate feed supplements with HMC without added phytase. The Medium diets were achieved by mixing a 50:50 blend of the High and Low diets. All Phase II diets were achieved by mixing a 50:50 blend of the appropriate Phase I and Phase III diets. Complete diet and faecal samples were obtained during weeks 3 and 6 after weaning for evaluation of accuracy of feed mixing and determination of nutrient digestibility. A minimum of six samples were obtained for each dietary treatment. Random samples of uncontaminated faecal material that had accumulated over a 2-d period were collected from at least four locations in the slatted area of each pen and pooled.
Pigs fed the Phy treatment had increased digestibility of crude protein (P<0.05) and P (P=0.062) in Phase III, and increased metacarpal breaking strength (P<0.01) and P content (P<0.05). Average daily gain, feed intake, and carcass composition were not affected by treatment (P>0.05).
It is concluded that performance of starter pigs fed liquid HMC-based diets was maintained at dietary P levels below the established requirements, but the addition of phytase improved bone strength and mineralization.
D Columbus; CL Zhu; JR Pluske, and CFM de Lange, C.F.M., 2010. Canadian Journal of Animal Science, 90:45-55.
