Effects of the Feed: Water Mixing Proportion on Diet Digestibility of Growing Pigs

SIMPLE SUMMARY: The effect of different water-to-feed ratios on apparent total tract digestibility was evaluated in growing–finishing pigs. Interest in giving pigs wet feed has increased in recent decades. However, there are still many concerns about doing it efficiently. In this study, the effects of different water-to-feed ratios on the digestibility of energy and nutrients in growing–finishing pigs were evaluated. Our results demonstrate that the optimal water-to-feed ratio to improve organic matter and gross energy digestibility varies depending on the age of the animal. In particular, the water-to-feed ratios that improve digestibility coefficients were lower for young growing pigs and higher for older finishing pigs. The data suggest that optimum efficiency is reached with a less water-diluted diet for young animals, when compared to older pigs. ABSTRACT: The effect of different water-to-feed ratios on apparent total tract digestibility of energy and nutrients were evaluated in growing–finishing pigs. In trial 1 (26 d), 16 female pigs (46.7 ± 1.98 kg of body weight, BW) were individually assigned to four treatments (n = 4). In trial 1, pigs were fed a control diet in dry form (CON) and in blend form with water-to-feed ratios of 0.6:1, 2.1:1 and 2.7:1. In trial 2 (26 d), rearranged animals (65.4 ± 3.14 kg of BW) were assigned a control diet in dry form (CON) and ratios of 1.35:1, 2.7:1 and 3.5:1. In trial 1, pigs fed on ratios of 2.1:1 and 2.7:1 had a higher organic matter digestibility (OMd) and gross energy digestibility (GEd) than CON. In trial 2, pigs fed on ratios of 1.35:1, 2.7:1, and 3.5:1 had a higher OMd and GEd than CON. Quadratic regressions showed the maximum dilution rate to reach higher digestibility coefficients at 1.83:1 and at 2.7:1 for trials 1 and 2, respectively. During trial 1, pigs on the 0.6:1 dilution rate had higher weight gain than those on CON. The water-to-feed ratio that optimized OM and GE digestibility may increase with the age of the pigs.