PSX-21 Diet and preslaughter stress effects on gut microbial populations and meat quality characteristics in goats

Abstract

Abstract Feeding condensed tannin (CT)-containing diets and minimizing preslaughter stress have been reported to improve meat quality and food safety in small ruminants. An experiment was conducted to determine the effects of feeding sericea lespedeza (SL), a high-CT legume, and transportation stress on gut microbial counts and meat quality in goats. In a completely randomized design with split-plot, thirty-six uncastrated male Spanish goats (Age = 8 mo; BW = 26.0 ± 0.48 kg) were assigned to one of 3 dietary treatments (n = 12): ground ‘Serala’ SL hay (SER), bermudagrass hay (BG), or bermudagrass hay - dewormed goats (BG-DW) at 75% of intake, with a corn-based supplement (25%) for 8 weeks. At the end of the trial, goats were either transported for 90 min to impose stress or held in pens before slaughtering in two replicates. Hot and cold carcass weights were lowest in SER, highest in BG-DW, and intermediate in BG group (P < 0.01). Longissimus muscle initial pH was not affected by diet or stress; however, the L* values were lower in SER compared with BG or BG-DW (P < 0.01). Diet or stress treatment did not have a significant effect on rumen and rectal pH values or E. coli and coliform counts. Rumen E. coli counts were 0.32, 0.35, and 0.32 (SEM = 0.088) log10CFU/g, respectively, in SER, BG, and BG-DW groups. The SER group had the lowest aerobic plate counts (APC) in both rumen and rectum (P < 0.01). Rumen APC were 4.74, 6.74, and 6.95 (SEM = 0.420) log10CFU/g, respectively, in SER, BG, and BG-DW groups. The results indicate that diet and stress did not notably influence meat quality characteristics studied or gut E. coli counts in goats, although there is evidence that APC in rumen and feces can be reduced by feeding SL for 8 weeks.