A comparison between feeding plasma and peptide proteins on nursery pig growth performance and intestinal health

A feeding experiment was conducted to demonstrate similar growth performance and carcass quality in grow-finish pigs fed diets containing ”Bt” corn as compared to ”non-Bt” corn. Bt corn resists the European Corn Borer by expressing the Cry1Ab selective insecticidal protein from Bacillus thuringiensis. Pigs (n=180; DeKalb EB x 45; 30 5.2 kg BW) were randomly assigned to one of three dietary treatments: diets containing 1) Bt corn (Bt); 2) the near isogenic control to the Bt corn (NIC); or 3) commingled conventional, non-genetically modified, corn hybrids (CC). The experimental diets were fed in four phases, and were formulated to contain equal percentages of each corn source within each phase. Pig growth rates were similar between corn sources (P>.10) at all time points. Barrows had greater overall ADG, ADFI, and lower feed efficiency (G:F) than gilts (P<.01). Pigs were harvested at 121 kg and carcass data collected. Pigs fed CC had greater HCW and dressing percentage (P<.05) than pigs fed NIC or Bt. Pigs fed NIC had greater 10th rib fat depth than either Bt or CC fed pigs (P<.05). Pigs fed the NIC corn had lower predicted percent lean than CC fed pigs (P<.05), but similar percent lean to Bt fed pigs. Pigs fed NIC had greater visible loin marbling than CC fed pigs (P<.05) and barrows had greater visible loin marbling than gilts (P<.05). Gilts had greater loin eye area and less backfat at the 10th and last rib (P<.05) and greater predicted percent lean than barrows (P<.05). DNA was extracted from loins of 12 pigs fed Bt and 12 pigs fed NIC diets. Southern blot analysis of PCR products was performed to screen for the presence of specific fragments of the cry1Ab and the endogenous corn protein Shrunken-2 (sh-2) genes. None of the extracted DNA samples were positive for cry1Ab or sh-2 genes. Also, using a competitive immunoassay cryIAb protein was not detected in the extracts of loin samples from pigs fed Bt corn. Results indicate pig growth performance and carcass characteristics are similar in pigs fed diets containing ”Bt” or ”non-Bt” corn. Furthermore, no evidence of passage of the transgene from the corn to the pigs tissue was found.