Author: LUIS ANGEL LARA FUENTES
The objective of the present study was to evaluate and compare the in vitro cecal fermentation (by the gas production technique), in Mexican hairless pig (MHP) and Mexican cuino pig (MCP), adding cellulose or starch as substrates (0, 100, 200, 300 and 400 mg/g DM). 12 pigs were slaughtered (BW= 104±0.5 kg), six of each genotype were collected from the cecal contents and there was a pool for every two pigs in each genotype, and thereafter, for each substrate (cellulose or starch) in its different concentration, three flasks were incubated with inoculum for each pool and made three series of incubation. The experimental design use the effect of genotype, substrate and concentration of the substrate added on the variables of in vitro fermentation. The averages of the data were compared by Tukey's method. In vitro gas production was higher (P<0.05) (mL/g DM) for MHP (206.8) vs MCP (180.2). The degradation fractional rate rhythm (b, 0.094 and c, -0.0127) and lag time (1.79) of the MHP was higher than MCP (b, 0.074; c -0.102) and lag time (1.26); with the addition of carbohydrates as substrates, in vitro gas production of potato starch was higher (P<0.05) than cellulose (238.3 vs 148.7 mL/g DM); the fractions b, c and lag time, there were differences (P<0.05) between substrates. The increasing addition of cellulose or starch had a lineal effect (P<0.05) with the gas production, level cero mg (133.46) to 400 mg of substrate (263.16 mL/g DM). MHP had a higher cecal fermentation than MCP, being higher the gas production at 9 and 12 h, there was higher gas production (cecal fermentation) when added starch as substrate.