Effect of feeding maltodextrins and dextrose on rearing and slaughtering performance of immunocastrated male pigs.

This study aimed to verify previous research findings showing that feeding maltodextrins (M) and dextrose (D) leads to a reduction of voluntary feed intake in the Italian heavy pig; this may be interesting for immunocastrated pigs fed ad libitum, whose feed intake skyrockets after the 2nd vaccination, causing too fatty carcasses at slaughtering. Thirty-six male pigs (Italian Duroc x Italian Large White crossbred) received a double immunocastrating injection at 90 and 162 days of age. At 120 days, weighing 51.84+4.38 kg, the subjects were evenly housed in 9 boxes, fed ad libitum till the 2nd injection and then given, until slaughtering (197 days of age; 144.51±9.70 kg), one of the experimental diets: control diet, ad libitum (CL); control diet, restricted at 7.5% l.w.0.75 (CR); with MD (3.5 + 3.5%; adjusted for energy and protein by lowering corn meal while increasing barley, soybean meal, and wheat bran), ad libitum (MD). The CR diet was introduced as the alternative choice to avoid too fatty carcasses. Compared to the restricted ones, pigs fed ad libitum during the entire trial (with or without MD) showed higher ADG (1265 and 1260 vs 1085 g/d), ADFI (3780 and 3833 vs 2943 g/d), feed:gain ratio (3.00 and 3.05 vs 2.72) and heavier carcasses (125.13 and 124.40 vs 113.25 kg), with lower lean meat content (52.21 and 52.09 vs 55.83 %). The results point out how immunocastrated pigs fed ad libitum showed similar rearing and slaughtering performance regardless of the inclusion of maltodextrins and dextrose in the diet.