Comparative efficacy of a blend of multiple enzymes and an in-feed antibiotic on growth performance and apparent digestibility of energy and protein in nursery pigs

Traditionally, in-feed antibiotics have been used as growth stimulants and to control gastrointestinal tract pathogens in pigs (Pluske et al. 2002). However, because of the perceived risks posed to human health by animal agriculture via the emergence of antibiotic-resistant bacteria, evaluation of alternatives to antibiotics is a topical area of research. There is accumulating evidence that added feed enzymes may aid the pig overcome digestive and enteric health challenges associated with weaning (Pluske et al. 2002; Kiarie et al. 2013). Few studies have investigated comparative effects of an antibiotic and feed enzymes on post-weaning performance. It was hypothesised that an antibiotic and a multi-enzyme blend (ME) will result in similar growth performance of nursery pigs. The objective of the study was to investigate the comparative efficacy of an antibiotic and ME on growth performance and apparent total tract digestibility in weaned pigs fed a corn-soybean meal based diet.

Seventy-two pigs (6.6 ± 0.1 kg; mean ± SD) were used in a two-phase trial (Phase 1, d 0–14; Phase 2, d 15–42). Diets were: Positive control (PC) + antibiotic (0.5% Mecadox; Phibro Animal Health, Fairfield, NJ); Negative control (NC, no additives); and NC + ME (ME, 4000 U of xylanase, 150 U of β-glucanase, 500 U of protease and 1000 U/kg of amylase per kg of feed; Danisco UK Ltd). The PC and NC basal diets were based on corn and soybean meal and were formulated to meet NRC (2012) specifications except that the NC diet had 5% less digestible energy (DE). In PC, DE and standardised ileal digestible lysine contents were 14.8 MJ/kg and 14 g/kg, respectively, in Phase I, and corresponding specifications for Phase 2 were 14.7 and 12.5 g/kg, respectively. All diets had 0.3% acid insoluble ash, 500 FTU of phytase/kg, and were fed in mash form. Each diet was allotted to eight pens with three pigs per pen. Pigs had free access to feed and water. Feed intake and body weight (BW) were measured weekly to determine average daily feed intake (ADFI), average daily gain (ADG) and gain to feed (G : F). Grab samples of faeces were collected 3 days at the end of each phase to determine the coefficient of total tract apparent digestibility (CTTAD). Data were analysed using PROC GLM procedures (SAS^®; USA).

Pig fed PC and ME had higher (P < 0.05) ADG than NC fed pigs in Phase 1 (Table 1). In Phase 2, pigs fed PC had higher (P < 0.05) ADG than ME which was in turn similar (P > 0.05) to that of NC-fed pigs. Pigs fed PC were heavier (P < 0.05) at the end of the trial (BW 42) than NC. Treatments did not affect (P > 0.05) ADFI whilst PC fed pigs had higher (P < 0.05) G : F in Phase 1. In both phases, pigs fed PC and ME diets had higher (P < 0.05) CTTAD of GE and CP than NC-fed pigs. A supplemental multi-enzyme blend caused similar performance and CTTAD of GE and CP to pigs fed an antibiotic in the early phase of weaning, suggesting that a feed enzyme mix such as that used in the present study could be a tool for managing the growth performance challenges immediately after weaning.

Table 1.  Effects of feeding an antibiotic and a multi-enzyme blend on growth performance and coefficients of total tract apparent digestibility (CATTD) in nursery pigs