Digestibility of high fibre diets and performance of growing Zimbabwean indigenous Mukota pigs and exotic Large White pigs fed maize based diets with graded levels of maize cobs

A comparative study was performed to determine the digestibility and performance in Zimbabwean indigenous Mukota pigs and exotic Large White pigs fed high fibre diets. Maize cob meal was used as the source of dietary fibre at levels of 0, 100, 200 and 300 g/kg. In the digestibility experiment (Experiment 1), four male pigs from each breed were used in a Latin square design. In the feeding trial (Experiment 2), 16 male pigs from each of the two breeds were used in a 2×4 factorial. Polynomial regression analysis was used to determine the relationship between maize cob levels with digestibility of nutrients, feed intake, average daily gain (ADG) and feed conversion ratio (FCR). In Experiment 1, increasing fibre levels in the diets resulted in a linear decrease (P<0.05) in the apparent digestibility of energy, crude protein (CP), neutral detergent fibre and acid detergent fibre for both breeds, except for dry matter (DM) CF in the Mukota, which exhibited a quadratic decrease. The rate of decrease in digestibility of all the nutrients was greater in Large White than Mukota pigs. In the feeding trial, there was no effect (P>0.05) of maize cob level on feed intake for both Large White and Mukota pigs. The decrease in ADG in the Large White was linear (β=0.0043; R2=0.976) and quadratic in the Mukota pigs (P<0.05). Large White pigs showed a higher rate of decrease in feed efficiency (β=0.0348; R2=0.936) than Mukota pigs (β=0.0115; R2=0.832; P<0.05) as the fibre level increased. It is concluded that maize cob inclusion reduces nutrient utilisation in both breeds, although Mukota pigs can utilise high fibre diets better than Large White pigs. These findings suggest that indigenous Mukota pigs are more appropriate to use than Large White pigs where high fibre diets are the available feed resources.