Determining the effects of tryptophan biomass on growth performance of 11 to 23 kg nursery pigs

A total of 320 barrows (DNA 200×400, initially 11.3 ± 0.65 kg BW) were used in a 21-d growth trial evaluating the effects of feeding Trp biomass (CJ America-Bio, Downers Grove, IL) as a source of Trp on nursery pig performance. Pigs were weaned at approximately 21 d of age, placed in pens based on initial BW, and fed a common diet. On d 21 after weaning, pigs were weighed and pens were allotted to 1 of 4 dietary treatments with 5 pigs/pen and 16 replicates/treatment. Dietary treatments included a negative control (16% SID Trp:Lys), positive control (21% SID Trp:Lys from crystalline L-Trp), or diets containing Trp biomass to provide 21 or 23.5% SID Trp:Lys (included at 0.104 or 0.156% of the diet, respectively). Diets were cornsoybean meal based and contained 1.25% SID Lys with other AA set to meet or exceed NRC (2012) requirement estimates. The Trp biomass contained 69% Trp. Growth data were analyzed as a randomized complete block design using PROC GLIMMIX of SAS with pen as the experimental unit. Overall (d 0 to 21) pigs fed 21% Trp from L-Trp or Trp biomass had increased (P < 0.05) ADG compared to the control, with pigs fed the 23.5% SID Trp biomass intermediate. Pigs fed the 21% Trp from Trp biomass had improved (P < 0.05) G:F compared to the control with others intermediate. In conclusion, Trp biomass is a viable alternative to crystalline Trp, but further evaluation at higher inclusion levels is needed.