NSP-ase and phytase improve growth performance and upholds carcass traits

It has been largely established that non-starch polysaccharides degrading enzymes (NSP-ase) are able to improve digestibility of nutrients in growing and finishing pigs fed on common ingredients (Emiola et al. 2009; Cozannet et al. 2012), but research on the effect of dietary enzymes on carcass quality in pigs remains scarce. The aim of this study was to evaluate the effect of a combination of NSP-enzymes and phytase on the performance and carcass traits in growing and finishing pigs fed reformulated wheat-, wheat bran- and soybean meal-based diet.

The study was conducted in Schothorst Feed Research facility, The Netherlands. In total, 360 crossbred gilts (Talent x (Great Yorkshire × Finnish Landrace)) with an average liveweight of 23.8 kg were used in the trial, which consisted of three treatments with 12 replicates of 10 pigs per replicate. The three treatments included: (1) positive control (PC), formulated as a typical commercial Dutch diet; (2) negative control (NC), reduced NE: –100 kcal/kg, calcium (Ca): –0.8 g/kg and digestible phosphorous (P): –1.0 g/kg, in accordance with the manufacturer’s guidance; (3) negative control + NSP-enzymes (Rovabio, Adisseo, Singapore) 200 mL/mt, containing mainly the activities of xylanase and β-glucanase + phytase 500 FTU/kg. Feed (pellets) and water were provided ad libitum. The pigs received a grower diet during the first 5 weeks followed by a finisher diet until the end of the experiment. At the end of the experiment, 12 pigs per treatment were killed to determine bone ash content (fat-free basis) in the metacarpus 2. Carcass weight, back fat thickness, muscle thickness and lean meat percentage were assessed per pig after slaughtering. Results were screened for outliers using the Doornbos test and subsequently statistically analysed as a randomised block design by ANOVA, using Genstat 14 (VSN International, Hemel Hempstead, UK). If a significant treatment effect was found, the least significant difference test (l.s.d.) was used for comparing treatment means. Differences were considered to be significant when P < 0.05.

Growth performance of the pigs is presented in Table 1. Compared with the PC, the reduction of nutrients (NC) significantly (P < 0.001) decreased weight gain, and numerically decreased feed intake and feed efficiency. The enzyme supplementation significantly improved weight gain (P < 0.001), and partially improved feed intake and feed efficiency. In terms of carcass traits, the reformulation significantly reduced bone ash content (–4.13%, P < 0.001), but the addition of the enzymes restored this parameter to the same level of the PC group. Lowering the specifications in NE, Ca and P led to a significant (P < 0.001) decrease of carcass weight without affecting meat percentage, back fat and muscle thickness. Adding the enzymes to the reformulated diet significantly (P < 0.001) improved carcass weight percentage. The results indicate that down-specification on energy, Ca and P has detrimental effect on performance and carcass traits, and the addition of NSP-ase, and phytase is capable of degrading cell wall constituents and phytic acids, hence can improve the digestibility of key nutrients, and restore performance and some carcass characteristics. In conclusion, the results clearly demonstrate the benefits of supplementing both NSP-ase and phytase to diets of grower and finisher pigs. Moreover, exogenous enzymes can restore bone ash and carcass weight in pigs fed on a nutritionally marginal wheat diet.

Table 1.  Effect of the NSP-enzyme + phytase on growth performance and carcass traits