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The interaction between enzyme supplementation and lactose level on the performance of weanling pigs fed barley based diets
Livestock Science 108 (2007) 258 – 261 www.elsevier.com/locate/livsci
The interaction between enzyme supplementation and lactose level on the performance of weanling pigs fed barley based diets ☆ M.B. Lynch ⁎, J.J. Callan, J.V. O'Doherty School of Agriculture, Food Science and Veterinary Medicine, Lyons Research Farm, University College Dublin, Ireland
Abstract A 2 × 2 factorial arrangement was used to investigate the interaction between lactose level (170 vs. 275 g/kg) and enzyme supplementation (with or without Endo-1,3 (4)-β-glucanase) in barley based diets (250 g/kg) on piglet performance post weaning. Ninety six weaned piglets (24 days old, 6.5 kg live weight) were blocked on the basis of live weight and were assigned to one of 4 dietary treatments (n = 6) for 21 days. There was an interaction (P b 0.05) between lactose level and β-glucanase supplementation on average daily gain (ADG), food conversion ratio (FCR) and apparent digestibilities of dry matter (DMD), organic matter (OMD) and nitrogen (N). Pigs offered 170 g/kg lactose and β-glucanase supplementation had an improved FCR and ADG compared to the 170 g/kg lactose and unsupplemented barley. However, β-glucanase supplementation at 275 g/kg lactose had no effect on FCR and ADG compared to the 275 g/kg lactose and untreated barley. Pigs offered the diet containing the low level of lactose and βglucanase supplementation increased (P b 0.05) DMD, OMD and N digestibility compared to the β-glucanase supplemented high lactose diet. However, there was no effect of lactose level in the unsupplemented diets. In conclusion, the inclusion of β-glucanase at the 170 g/kg lactose level improved ADG, FCR and diet digestibility. β-glucanase had a negative effect on FCR and ADG at the 275 g/kg lactose level. © 2007 Elsevier B.V. All rights reserved. Keywords: Barley; Enzyme; Lactose; Pigs
1. Introduction Elevated levels of β-glucan, can cause an increase in digesta viscosity, preventing interaction between nutrients and digestive enzymes and leading to reduced nutrient utilisation. The addition of enzyme preparations can effectively degrade viscous NSP in the diet leading to a reduction in the viscosity of the diet and in enhanced ☆ This paper is part of the special issue entitled “Digestive Physiology in Pigs” guest edited by José Adalberto Fernández, Mette Skou Hedemann, Bent Borg Jensen, Henry Jørgensen, Knud Erik Bach Knudsen and Helle Nygaard Lærke. ⁎ Corresponding author. E-mail address: [email protected] (M.B. Lynch).
1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.01.066
nutrient utilisation (Dierick and Decuypere, 1996). However, the beneficial effects of β-glucan such as the increased proliferation of Lactobacillus and Bifidobacterium spp. and a reduction in pathogenic bacteria (O'Connell et al., 2005) maybe removed as a result of enzyme preparations. In the weanling pig, dietary lactose is readily fermented to lactic acid by intestinal lactic acid bacteria (Partridge and Gill, 1993) which reduces the pH of the stomach and creates conditions unfavourable for the multiplication of E. coli thereby improving gastrointestinal health. The hypothesis of the current experiment is that the β-glucan present in barley could substitute for lactose as a substrate for microbial fermentation in the large intestine and this would allow
M.B. Lynch et al. / Livestock Science 108 (2007) 258–261 Table 1 Composition and analysis of experimental starter diets (as fed) Composition (g/kg) β-glucanase (mg/kg) Whey permeate Barley Wheat Soya bean meal Whey protein isolate Full fat soya Soya Oil Vitamins and minerals Lysine HCl DL-Methionine L-Threonine Chromic oxide
0 150 250.0 189.0 150.0 125.0 60.0 65.0 5.0 4.2 1.5 0.3 0.15
0 300 250.0 49.0 150.0 125.0 60.0 55.0 5.0 4.2 1.5 0.3 0.15
0.15 150 250.0 189.0 150.0 125.0 60.0 65.0 5.0 4.2 1.5 0.3 0.15
0.15 300 250.0 49.0 150.0 125.0 60.0 55.0 5.0 4.2 1.5 0.3 0.15
Analysis (g/kg) Dry matter Crude protein (N × 6.25) Neutral-detergent fibre Ash Gross energy (MJ/kg) Lysine a Methionine and cysteine a Threonine a Tryptophan a
898.4 188.0 93.6 40.8 17.9 16.0 9.6 10.4 2.9
913.1 199.7 79.2 51.0 17.7 16.0 9.6 10.4 2.9
906.0 192.4 93.6 41.2 17.3 16.0 9.6 10.4 2.9
913.9 199.9 79.2 52.0 17.9 16.0 9.6 10.4 2.9
259
and barley (250 g/kg) plus β-glucanase. The experimental enzyme supplement was derived from Penicillium funiculosum (IMI SD 101) and contained endo-1, 3 (4)-β-glucanase added at 0.15 mg/kg. The diets were formulated to have identical concentrations of digestible energy (16 MJ/kg) and ideal protein (Close, 1994). Chromic oxide was added to all diets at the rate of 150 ppm. The ingredient composition and chemical analysis of the diets are presented in Table 1. 2.2. Animals and management Ninety six piglets (initial live weight of 6.50 kg, S.D. = 0.74 kg) were blocked on the basis of initial live weight and within each block assigned to one of 4 treatments. The piglets were housed in groups of 4 on fully slatted floors (1.68 m × 1.22 m). Faeces samples were collected from each pen from day 10– 14 and were retained for chemical analysis. Fresh faecal samples were also taken from each pen on days 14 and 21 for pH determination. 2.3. Laboratory analysis
a Calculated from proximate analyses (Ministry of Agriculture, Fisheries and Food, 1991).
the level of dietary lactose to be reduced while maintaining performance. However, exogenous βglucanase enzymes may remove specific substrates for microbial fermentation limiting the potential of βglucans in barley. 2. Materials and methods 2.1. Experimental diets The experiment was designed as a 2 × 2 factorial consisting of 4 dietary treatments. The treatments were: (1) 170 g/kg lactose and barley (250 g/kg), (2) 275 g/kg lactose and barley (250 g/kg), (3) 170 g/kg lactose and barley (250 g/kg) plus β-glucanase, (4) 275 g/kg lactose
Proximate analysis of diets for dry matter and ash was carried out according to AOAC (1995). The neutral detergent fibre (NDF) content of feed was determined according to the method of Van Soest et al. (1991). The nitrogen content of feed was determined using the LECO FP 528 instrument (Leco Instruments, Ltd, Cheshire, UK). The nitrogen content of faeces was analysed by the macro-Kjeldahl technique using a Buchii distillation apparatus. The gross energy of feed and faecal samples was determined using a Parr 1201 oxygen bomb calorimeter (Parr, Moline, Illinois, USA). The chromium concentration was determined according to Williams et al. (1962). 2.4. Statistical analysis Both the performance and digestibility studies were analysed as a 2 × 2 factorial using the General Linear
Table 2 Interaction between lactose level and β-glucanase inclusion on pig performance (LSM ± SEM) β-glucanase
−
−
+
+
Significance
Lactose Level (g/kg)
170
275
170
275
SEM
Lactose
β-glucanase
Lactose × β-glucanase
Overall ADG (kg/day) Overall feed intake (kg/day) Overall FCR (kg/kg)
0.278 0.464 2.192
0.303 0.479 1.616
0.330 0.515 1.690
0.291 0.474 1.844
0.018 0.024 0.139
ns ns ⁎
ns ns ns
⁎ ns ⁎
⁎ = (P b 0.05), ns = non significant (P N 0.05).
260
M.B. Lynch et al. / Livestock Science 108 (2007) 258–261
Table 3 Interaction between lactose level and β-glucanase inclusion on apparent digestibility of diets (LSM ± SEM) β-glucanase
−
−
+
+
Lactose Level (g/kg)
170
275
170
275
SEM
Lactose
β-glucansae
Lactose × β-glucanase
Digestibility coefficients Dry matter Organic matter Nitrogen Ash Neutral detergent fibre Gross energy Faeces dry matter Faecal pH
0.849 0.862 0.780 0.582 0.451 0.826 234.9 6.047
0.853 0.865 0.770 0.653 0.468 0.825 236.9 6.250
0.881 0.891 0.834 0.677 0.529 0.862 239.5 6.260
0.867 0.879 0.791 0.673 0.536 0.843 216.4 6.233
0.047 0.044 0.017 0.013 0.019 0.059 12.12 0.083
ns ns ⁎ ⁎⁎ ns ns ns ns
⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ns ns
⁎ ⁎ ⁎ ⁎ ns ns ns ns
Significance
⁎ = (P b 0.05), ⁎⁎ = (P b 0.01), ⁎⁎⁎ = (P b 0.001), ns = non significant (P N 0.05).
Model procedure of the SAS Institute (1985). The models for both the performance and digestibility analysis included the main effects of lactose level, enzyme supplementation and the associated 2 way interaction. Both the performance and digestibility data were adjusted for initial live weight by covariance analysis.
digestibility of dry matter (DMD), organic matter (OMD), nitrogen and ash (Table 3). Pigs offered diets containing 170 g/kg lactose plus β-glucanase had higher DMD, OMD, N and ash digestibility compared to the 275 g/kg lactose plus β-glucanase diet. However, there was no significant effect of lactose level in the unsupplemented diets.
3. Results
4. Discussion
3.1. Performance study
Enzyme supplementation of barley based diets at low lactose concentration improved ADG and FCR as well as improving DM, OMD, N and ash digestibility. However, enzyme inclusion had no effect on performance at the high lactose concentration. It maybe assumed that β-glucanase failed to enzymatically degrade the β-glucan present in barley in the high lactose diets. The β-glucanase enzyme must resist proteolysis by the animal's endogenous proteases and the acidic environment of the pig's stomach in order to have its desired effect (Baas and Thacker, 1996). The positive response in pig performance to β-glucanase in the low lactose diets would confirm its survival and activity. However, there was no response to β-glucanase supplementation at the high level of dietary lactose on pig performance, this maybe due to low intestinal pH. It was found that the optimal pH range for effective βglucanase activity is 4.5–5.5 and a pH below 3.5 in the stomach was clearly detrimental to β-glucanase activity (Baas and Thacker, 1996). Pierce et al. (2006) reported an average stomach pH of 3.65 with lactose diets fed similar in composition to this study. It is therefore possible that the acidification of the gastro intestinal tract due to inclusion of high levels of lactose caused the enzyme to be hydrolysed. In conclusion, β-glucanase supplementation improved diet digestibility and pig performance at low
There was an interaction (P b 0.05) between lactose level and enzyme supplementation on ADG and FCR during the starter period (Table 2). Pigs offered the diet containing 170 g/kg lactose plus β-glucanase had a significantly higher ADG compared to pigs offered the unsupplemented 170 g/kg lactose diet. However, there was no significant effect of pigs offered the diet containing 275 g/kg lactose plus β-glucanase compared to pigs offered the unsupplemented 275 g/kg lactose diet. Pigs offered 170 g/kg lactose plus β-glucanase had a better FCR compared to the unsupplemented 170 g/kg lactose diet (Table 2). However, pigs offered the diet containing 275 g/kg lactose plus β-glucanase had a poorer FCR compared to pigs offered the unsupplemented 275 g/kg lactose diet (P b 0.05). 3.2. Digestibility study Pigs offered β-glucanase supplemented diets had a higher apparent digestibility of gross energy (85.3 v. 82.6; SEM 0.421; P b 0.001) and NDF (53.3 vs 46.0; SEM 1.408; P b 0.001) than non enzyme supplemented diets. There was an interaction (P b 0.05) between lactose level and enzyme supplementation in the apparent
M.B. Lynch et al. / Livestock Science 108 (2007) 258–261
lactose levels. There was no response of β-glucanase supplementation to high levels of lactose. References Association of Official Analytical Chemists, 1995. Official Methods of Analysis16th ed. AOAC, Washington D.C., U.S. Baas, T.C., Thacker, P.A., 1996. Impact of gastric pH on dietary enzyme activity and survivability in swine fed β-glucanase supplemented diets. Canadian Journal of Animal Science 76, 245–252. Close, W.H., 1994. Feeding new genotypes: establishing amino acid/ energy requirements. In: Cole, D.J.A., Wiseman, J., Varley, M.A. (Eds.), Principals of Pig Science. Nottingham University Press, United Kingdom, pp. 123–140. Dierick, N., Decuypere, J., 1996. Mode of action of exogenous enzymes in growing pig nutrition. Pig News and Information 17, 41N–48N. O'Connell, M., Callan, J.J., Byrne, C., Sweeney, T., O'Doherty, J.V., 2005. The effect of cereal type and exogenous enzyme supplementation in pig diets on nutrient digestibility, intestinal
261
microflora, volatile fatty acid concentration and manure ammonia emissions from pigs. Animal Science 81, 357–364. Partridge, G.G., Gill, B.P., 1993. In: Wiseman, J., Garnsworthy, P.C. (Eds.), New Approaches with Pig Weaner Diets. Recent Developments in Pig Nutrition, vol. 3. Nottingham University Press, pp. 205–237. Pierce, K.M., Sweeney, T., Brophy, P.O., Callan, J.J., Fitzpatrick, E., McCarthy, P., O'Doherty, J.V., 2006. The effect of lactose and inulin on intestinal morphology, selected microbial populations and volatile fatty acid concentrations in the gastro-intestinal tract of the weanling pig. Animal Science 82, 311–318. Statistical Analysis Systems Institute, 1985. Statistical Analysis Systems, Version 6.12. SAS Institute Inc., Cary, NC. Van Soest, P.J., Robertson, J.B., Lewis, B.A., 1991. Methods for dietary fibre, neutral detergent fiber and non starch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74, 3583–3597. Williams, C.H., David, D.J., Iismaa, O., 1962. The determination of chromic oxide in faeces samples by atomic absorption spectrophotometry. Journal of Animal Science 59, 381–385.
The interaction between enzyme supplementation and lactose level on the performance of weanling pigs fed barley based diets ☆ M.B. Lynch ⁎, J.J. Callan, J.V. O'Doherty School of Agriculture, Food Science and Veterinary Medicine, Lyons Research Farm, University College Dublin, Ireland
Abstract A 2 × 2 factorial arrangement was used to investigate the interaction between lactose level (170 vs. 275 g/kg) and enzyme supplementation (with or without Endo-1,3 (4)-β-glucanase) in barley based diets (250 g/kg) on piglet performance post weaning. Ninety six weaned piglets (24 days old, 6.5 kg live weight) were blocked on the basis of live weight and were assigned to one of 4 dietary treatments (n = 6) for 21 days. There was an interaction (P b 0.05) between lactose level and β-glucanase supplementation on average daily gain (ADG), food conversion ratio (FCR) and apparent digestibilities of dry matter (DMD), organic matter (OMD) and nitrogen (N). Pigs offered 170 g/kg lactose and β-glucanase supplementation had an improved FCR and ADG compared to the 170 g/kg lactose and unsupplemented barley. However, β-glucanase supplementation at 275 g/kg lactose had no effect on FCR and ADG compared to the 275 g/kg lactose and untreated barley. Pigs offered the diet containing the low level of lactose and βglucanase supplementation increased (P b 0.05) DMD, OMD and N digestibility compared to the β-glucanase supplemented high lactose diet. However, there was no effect of lactose level in the unsupplemented diets. In conclusion, the inclusion of β-glucanase at the 170 g/kg lactose level improved ADG, FCR and diet digestibility. β-glucanase had a negative effect on FCR and ADG at the 275 g/kg lactose level. © 2007 Elsevier B.V. All rights reserved. Keywords: Barley; Enzyme; Lactose; Pigs
1. Introduction Elevated levels of β-glucan, can cause an increase in digesta viscosity, preventing interaction between nutrients and digestive enzymes and leading to reduced nutrient utilisation. The addition of enzyme preparations can effectively degrade viscous NSP in the diet leading to a reduction in the viscosity of the diet and in enhanced ☆ This paper is part of the special issue entitled “Digestive Physiology in Pigs” guest edited by José Adalberto Fernández, Mette Skou Hedemann, Bent Borg Jensen, Henry Jørgensen, Knud Erik Bach Knudsen and Helle Nygaard Lærke. ⁎ Corresponding author. E-mail address: [email protected] (M.B. Lynch).
1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.01.066
nutrient utilisation (Dierick and Decuypere, 1996). However, the beneficial effects of β-glucan such as the increased proliferation of Lactobacillus and Bifidobacterium spp. and a reduction in pathogenic bacteria (O'Connell et al., 2005) maybe removed as a result of enzyme preparations. In the weanling pig, dietary lactose is readily fermented to lactic acid by intestinal lactic acid bacteria (Partridge and Gill, 1993) which reduces the pH of the stomach and creates conditions unfavourable for the multiplication of E. coli thereby improving gastrointestinal health. The hypothesis of the current experiment is that the β-glucan present in barley could substitute for lactose as a substrate for microbial fermentation in the large intestine and this would allow
M.B. Lynch et al. / Livestock Science 108 (2007) 258–261 Table 1 Composition and analysis of experimental starter diets (as fed) Composition (g/kg) β-glucanase (mg/kg) Whey permeate Barley Wheat Soya bean meal Whey protein isolate Full fat soya Soya Oil Vitamins and minerals Lysine HCl DL-Methionine L-Threonine Chromic oxide
0 150 250.0 189.0 150.0 125.0 60.0 65.0 5.0 4.2 1.5 0.3 0.15
0 300 250.0 49.0 150.0 125.0 60.0 55.0 5.0 4.2 1.5 0.3 0.15
0.15 150 250.0 189.0 150.0 125.0 60.0 65.0 5.0 4.2 1.5 0.3 0.15
0.15 300 250.0 49.0 150.0 125.0 60.0 55.0 5.0 4.2 1.5 0.3 0.15
Analysis (g/kg) Dry matter Crude protein (N × 6.25) Neutral-detergent fibre Ash Gross energy (MJ/kg) Lysine a Methionine and cysteine a Threonine a Tryptophan a
898.4 188.0 93.6 40.8 17.9 16.0 9.6 10.4 2.9
913.1 199.7 79.2 51.0 17.7 16.0 9.6 10.4 2.9
906.0 192.4 93.6 41.2 17.3 16.0 9.6 10.4 2.9
913.9 199.9 79.2 52.0 17.9 16.0 9.6 10.4 2.9
259
and barley (250 g/kg) plus β-glucanase. The experimental enzyme supplement was derived from Penicillium funiculosum (IMI SD 101) and contained endo-1, 3 (4)-β-glucanase added at 0.15 mg/kg. The diets were formulated to have identical concentrations of digestible energy (16 MJ/kg) and ideal protein (Close, 1994). Chromic oxide was added to all diets at the rate of 150 ppm. The ingredient composition and chemical analysis of the diets are presented in Table 1. 2.2. Animals and management Ninety six piglets (initial live weight of 6.50 kg, S.D. = 0.74 kg) were blocked on the basis of initial live weight and within each block assigned to one of 4 treatments. The piglets were housed in groups of 4 on fully slatted floors (1.68 m × 1.22 m). Faeces samples were collected from each pen from day 10– 14 and were retained for chemical analysis. Fresh faecal samples were also taken from each pen on days 14 and 21 for pH determination. 2.3. Laboratory analysis
a Calculated from proximate analyses (Ministry of Agriculture, Fisheries and Food, 1991).
the level of dietary lactose to be reduced while maintaining performance. However, exogenous βglucanase enzymes may remove specific substrates for microbial fermentation limiting the potential of βglucans in barley. 2. Materials and methods 2.1. Experimental diets The experiment was designed as a 2 × 2 factorial consisting of 4 dietary treatments. The treatments were: (1) 170 g/kg lactose and barley (250 g/kg), (2) 275 g/kg lactose and barley (250 g/kg), (3) 170 g/kg lactose and barley (250 g/kg) plus β-glucanase, (4) 275 g/kg lactose
Proximate analysis of diets for dry matter and ash was carried out according to AOAC (1995). The neutral detergent fibre (NDF) content of feed was determined according to the method of Van Soest et al. (1991). The nitrogen content of feed was determined using the LECO FP 528 instrument (Leco Instruments, Ltd, Cheshire, UK). The nitrogen content of faeces was analysed by the macro-Kjeldahl technique using a Buchii distillation apparatus. The gross energy of feed and faecal samples was determined using a Parr 1201 oxygen bomb calorimeter (Parr, Moline, Illinois, USA). The chromium concentration was determined according to Williams et al. (1962). 2.4. Statistical analysis Both the performance and digestibility studies were analysed as a 2 × 2 factorial using the General Linear
Table 2 Interaction between lactose level and β-glucanase inclusion on pig performance (LSM ± SEM) β-glucanase
−
−
+
+
Significance
Lactose Level (g/kg)
170
275
170
275
SEM
Lactose
β-glucanase
Lactose × β-glucanase
Overall ADG (kg/day) Overall feed intake (kg/day) Overall FCR (kg/kg)
0.278 0.464 2.192
0.303 0.479 1.616
0.330 0.515 1.690
0.291 0.474 1.844
0.018 0.024 0.139
ns ns ⁎
ns ns ns
⁎ ns ⁎
⁎ = (P b 0.05), ns = non significant (P N 0.05).
260
M.B. Lynch et al. / Livestock Science 108 (2007) 258–261
Table 3 Interaction between lactose level and β-glucanase inclusion on apparent digestibility of diets (LSM ± SEM) β-glucanase
−
−
+
+
Lactose Level (g/kg)
170
275
170
275
SEM
Lactose
β-glucansae
Lactose × β-glucanase
Digestibility coefficients Dry matter Organic matter Nitrogen Ash Neutral detergent fibre Gross energy Faeces dry matter Faecal pH
0.849 0.862 0.780 0.582 0.451 0.826 234.9 6.047
0.853 0.865 0.770 0.653 0.468 0.825 236.9 6.250
0.881 0.891 0.834 0.677 0.529 0.862 239.5 6.260
0.867 0.879 0.791 0.673 0.536 0.843 216.4 6.233
0.047 0.044 0.017 0.013 0.019 0.059 12.12 0.083
ns ns ⁎ ⁎⁎ ns ns ns ns
⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ns ns
⁎ ⁎ ⁎ ⁎ ns ns ns ns
Significance
⁎ = (P b 0.05), ⁎⁎ = (P b 0.01), ⁎⁎⁎ = (P b 0.001), ns = non significant (P N 0.05).
Model procedure of the SAS Institute (1985). The models for both the performance and digestibility analysis included the main effects of lactose level, enzyme supplementation and the associated 2 way interaction. Both the performance and digestibility data were adjusted for initial live weight by covariance analysis.
digestibility of dry matter (DMD), organic matter (OMD), nitrogen and ash (Table 3). Pigs offered diets containing 170 g/kg lactose plus β-glucanase had higher DMD, OMD, N and ash digestibility compared to the 275 g/kg lactose plus β-glucanase diet. However, there was no significant effect of lactose level in the unsupplemented diets.
3. Results
4. Discussion
3.1. Performance study
Enzyme supplementation of barley based diets at low lactose concentration improved ADG and FCR as well as improving DM, OMD, N and ash digestibility. However, enzyme inclusion had no effect on performance at the high lactose concentration. It maybe assumed that β-glucanase failed to enzymatically degrade the β-glucan present in barley in the high lactose diets. The β-glucanase enzyme must resist proteolysis by the animal's endogenous proteases and the acidic environment of the pig's stomach in order to have its desired effect (Baas and Thacker, 1996). The positive response in pig performance to β-glucanase in the low lactose diets would confirm its survival and activity. However, there was no response to β-glucanase supplementation at the high level of dietary lactose on pig performance, this maybe due to low intestinal pH. It was found that the optimal pH range for effective βglucanase activity is 4.5–5.5 and a pH below 3.5 in the stomach was clearly detrimental to β-glucanase activity (Baas and Thacker, 1996). Pierce et al. (2006) reported an average stomach pH of 3.65 with lactose diets fed similar in composition to this study. It is therefore possible that the acidification of the gastro intestinal tract due to inclusion of high levels of lactose caused the enzyme to be hydrolysed. In conclusion, β-glucanase supplementation improved diet digestibility and pig performance at low
There was an interaction (P b 0.05) between lactose level and enzyme supplementation on ADG and FCR during the starter period (Table 2). Pigs offered the diet containing 170 g/kg lactose plus β-glucanase had a significantly higher ADG compared to pigs offered the unsupplemented 170 g/kg lactose diet. However, there was no significant effect of pigs offered the diet containing 275 g/kg lactose plus β-glucanase compared to pigs offered the unsupplemented 275 g/kg lactose diet. Pigs offered 170 g/kg lactose plus β-glucanase had a better FCR compared to the unsupplemented 170 g/kg lactose diet (Table 2). However, pigs offered the diet containing 275 g/kg lactose plus β-glucanase had a poorer FCR compared to pigs offered the unsupplemented 275 g/kg lactose diet (P b 0.05). 3.2. Digestibility study Pigs offered β-glucanase supplemented diets had a higher apparent digestibility of gross energy (85.3 v. 82.6; SEM 0.421; P b 0.001) and NDF (53.3 vs 46.0; SEM 1.408; P b 0.001) than non enzyme supplemented diets. There was an interaction (P b 0.05) between lactose level and enzyme supplementation in the apparent
M.B. Lynch et al. / Livestock Science 108 (2007) 258–261
lactose levels. There was no response of β-glucanase supplementation to high levels of lactose. References Association of Official Analytical Chemists, 1995. Official Methods of Analysis16th ed. AOAC, Washington D.C., U.S. Baas, T.C., Thacker, P.A., 1996. Impact of gastric pH on dietary enzyme activity and survivability in swine fed β-glucanase supplemented diets. Canadian Journal of Animal Science 76, 245–252. Close, W.H., 1994. Feeding new genotypes: establishing amino acid/ energy requirements. In: Cole, D.J.A., Wiseman, J., Varley, M.A. (Eds.), Principals of Pig Science. Nottingham University Press, United Kingdom, pp. 123–140. Dierick, N., Decuypere, J., 1996. Mode of action of exogenous enzymes in growing pig nutrition. Pig News and Information 17, 41N–48N. O'Connell, M., Callan, J.J., Byrne, C., Sweeney, T., O'Doherty, J.V., 2005. The effect of cereal type and exogenous enzyme supplementation in pig diets on nutrient digestibility, intestinal
261
microflora, volatile fatty acid concentration and manure ammonia emissions from pigs. Animal Science 81, 357–364. Partridge, G.G., Gill, B.P., 1993. In: Wiseman, J., Garnsworthy, P.C. (Eds.), New Approaches with Pig Weaner Diets. Recent Developments in Pig Nutrition, vol. 3. Nottingham University Press, pp. 205–237. Pierce, K.M., Sweeney, T., Brophy, P.O., Callan, J.J., Fitzpatrick, E., McCarthy, P., O'Doherty, J.V., 2006. The effect of lactose and inulin on intestinal morphology, selected microbial populations and volatile fatty acid concentrations in the gastro-intestinal tract of the weanling pig. Animal Science 82, 311–318. Statistical Analysis Systems Institute, 1985. Statistical Analysis Systems, Version 6.12. SAS Institute Inc., Cary, NC. Van Soest, P.J., Robertson, J.B., Lewis, B.A., 1991. Methods for dietary fibre, neutral detergent fiber and non starch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74, 3583–3597. Williams, C.H., David, D.J., Iismaa, O., 1962. The determination of chromic oxide in faeces samples by atomic absorption spectrophotometry. Journal of Animal Science 59, 381–385.