• Effect of phytase, carbohydrase, and protease addition to a wheat distillers dried grains with solubles and rapeseed based diet on in vitro ileal digestibility, growth, and bone mineral density of grower-finisher pigs

      Torres-Pitarch, Alberto; McCormack, Ursula M.; Beattie, Violet; Magowan, Elizabeth; Gardiner, Gillian; Pérez-Vendrell, Anna; Torrallardona, David; O'Doherty, John; Lawlor, Peadar G; European Union; et al. (Elsevier, 2018-07-07)
      The use of rapeseed meal (RSM) and wheat distillers dried grains with solubles (wDDGS) in pig diets is increasing and dietary supplementation with exogenous enzymes has been suggested as means of improving feed efficiency in pigs. The objective of this experiment was to examine the effect of phytase (Phy), a xylanase and β-glucanase complex (XB), protease (Prot) and their various combinations when included in a wDDGS- and RSM-based diet fed to grower-finisher pigs. As the P- and Ca- sparing effect of Phy is well proven, the objective was to examine the additional effects of Phy beyond its P- and Ca-sparing effects. A total of 144 pigs with an initial live weight of 40.1 ± 2.0 kg were assigned to 8 treatments with 9 pens (4 female and 5 male pens) per treatment and 2 females or 2 males per pen. The basal diet was formulated to contain 96 and 200 g/kg of RSM and wDDGS, respectively. The basal diet was supplemented with Phy (0 or 100 mg/kg), XB (0 or 100 mg/kg), and Prot (0 or 200 mg/kg) in a 2 × 2 × 2 factorial arrangement of treatments. Experimental diets were fed for 76 d. Average daily gain (ADG) and average daily feed intake (ADFI) were recorded, and gain to feed (G:F) was calculated. Carcass quality variables were measured at slaughter and the left forelimb of pigs fed the unsupplemented, the Phy supplemented and the Phy + Prot supplemented diets were removed to determine bone mineral density in the third metacarpal. The inclusion of Phy, XB and Prot in the diets increased in vitro ileal digestibility of dry matter and organic matter (P < 0.05). A tendency towards a 3-way interaction among Phy, XB and Prot was observed for ADG (P = 0.06) and G:F (P = 0.06). The 2-way interactions and main effects did not reveal any improvement for any variable measured in vivo in response to dietary enzyme supplementation. Bone mineral density was not different for pigs fed the unsupplemented, the Phy supplemented and the Phy + Prot supplemented diets. In conclusion, the in vitro ileal digestibility improvements observed were not always reflected in improvements in pig growth, feed efficiency or both. The efficacy of Phy was not reduced when supplemented in combination with Prot, as ADG, G:F, carcass quality and bone mineralization were unchanged.
    • Systematic review and meta-analysis of the effect of feed enzymes on growth and nutrient digestibility in grow-finisher pigs: Effect of enzyme type and cereal source

      Torres-Pitarch, Alberto; Manzanilla, Edgar G; Gardiner, Gillian E.; O'Doherty, John V.; Lawlor, Peadar G; Teagasc; European Union’s Seventh Framework Programme; Teagasc Walsh Fellowship Programme; PDPG6671; 311794 (Elsevier, 2019-12-28)
      Dietary supplementation of pig diets with exogenous enzymes has been suggested as a strategy to increase nutrient digestibility and improve feed efficiency in grow-finisher pigs. However, inconsistent results are found in the literature. Ingredient composition of the diets is one of the most important sources of variation that may affect enzyme efficacy and consistency of results. A systematic review and a meta-analysis was therefore conducted to determine which exogenous enzymes with which diet type most consistently improve pig growth, nutrient digestibility and feed efficiency. Enzyme type and dietary cereal source were the main explanatory variables included in the models. The mean difference effects of enzyme supplementation on average daily gain (ADG), average daily feed intake (ADFI), gain to feed (G:F), apparent ileal digestibility (AiD) and apparent total tract digestibility (ATTD) of dry matter (DM), crude protein (CP), and gross energy (GE) were calculated for each study and these were used as the effect size estimates in the meta-analysis. A dataset with 139 comparisons from 67 peer-reviewed publications was used in the meta-analysis. In response to enzyme supplementation, G:F was improved in 38 of the 120 comparisons reporting pig growth data, remained un-changed in 78 and deteriorated in 4. Overall, DM and GE AiD, and ATTD were improved by xylanase, xylanase + β-glucanase, mannanase and protease dietary supplementation (P < 0.05). Crude protein AiD was only improved by protease dietary supplementation (P < 0.001). Dietary supplementation with xylanase alone improved ADG of maize- (P < 0.05) and co-product- (P < 0.05) based diets but had no effect on the G:F of grow-finisher pigs. Dietary supplementation with xylanase + β-glucanase had no effect on ADG, ADFI and G:F. Protease supplementation tended to improve the ADG of grow-finisher pigs fed co-product-based diets (P = 0.08) but had no effect on G:F. Dietary supplementation with multi-enzyme complexes improved the ADG (P < 0.05) and G:F (P < 0.01) of maize-, wheat-, barley- and co-product-based diets. In conclusion, dietary supplementation with all enzyme types improved nutrient digestibility depending on ingredient content, while mannanase and multi-enzyme complex supplementation most consistently improved growth and feed efficiency.