Relative ileal amino acid flows and microbial counts in intestinal effluents of Goettingen Minipigs and Saddleback pigs are not different

We explored the suitability of Goettingen Minipigs as models to measure ileal AA digestibility and evaluate dietary proteins for conventional pigs. Further, a potential for secondary ileal microbial colonization 5 mo after establishing end-to-end ileorectal anastomosis was investigated. Goettingen Minipigs (BW 18 kg) and Saddleback pigs (BW 27 kg) fitted with end-to-end ileorectal anastomosis were fed six diets based on barley and oilseed meals and three diets based on wheat and milk powder differing in total and ileal digestible lysine. Apparent ileal digestibilities of CP (N x 6.25) and of 20 AA were determined. No differences (P = 0.062 to 0.982) were found in AA apparent ileal digestibilities between breeds. Therefore, Minipigs are a reasonable model to estimate apparent ileal digestibility of AA for evaluation of dietary proteins. However, the apparent ileal digestibility of CP (P = 0.048) was higher in Minipigs than in Saddleback pigs (barley and oilseed meals-based diets 70% vs. 66%; wheat and milk powder-based diets 80% vs. 77%), which is probably due to a smaller contribution of non-AA-nitrogen in the ileal effluent of Goettingen Minipigs. For lysine, the apparent ileal digestibilities (means of both breeds) ranged from 78 to 85% in wheat and milk powder-based, and 70 to 78% in barley and oilseed-based diets. Experimentally derived concentrations of ileally digestible lysine confirmed the values predicted from a published table. Microbial counts were not affected by breed as shown for lactobacilli, with 9.1+/-0.2 and 9.1+/-0.2 (P = 0.977), enterococci with 4.8+/-0.3 and 5.6+/-0.4 (P = 0.162), and yeasts with 4.6+/-0.3 and 4.6+/-0.4 (P = 0.906) log cfu/g effluent for Goettingen Minipigs and Saddleback pigs, respectively. The counts did not change over 5 mo, suggesting that no secondary microbial colonization occurred in pigs with end-to-end ileorectal anastomosis.