Screening Of Special Cocktail Enzyme For Double-low Rapeseed Meal Based Diet In Vitro And Its Application To Pigs And Poultry

In this study the "special cocktail enzyme" for double-low rapeseed meal(DLRM) based diet were screened out by the in vitro incubation system, and a feeding and digestibility trials were conducted to validate the effects of the "special cocktail enzyme" application to DLRM based diets for pigs and broilers, and to evaluate the relationship between nutrient digestibility and animal performance.Experiment 1: four enzymes numbered A, B, C, D with four arranged levels for each were selected in this experiment. Enzymes A, B, C, D were all non-starch polysaccharide enzymes: enzyme A is a fungal origin cellulase with multiple enzyme activities of endoglucanase (EC 3.2.1.4, 1,4-β-D-glucan glucanohydrose), exoglucanase or cellobiohydroase(EC 3.2.1.91, 1,4-β-D-glucan cellobihydrolase) and β-glucosidase or cellobiase(EC 3.2.1.21, β-D-glucoside glucohydrolase), enzyme B was a bacterial origin endoxylanase(EC 3.2.1.8, endo-1,4-β-D-xylanase), and enzymes C and D were fungal origin endoxylanase. Orthogonal experiments with four enzymes as four factors arranged in the table(L₁₆ (4⁵)) were carried out to evaluate the effects of different combinations of enzymes on the digestibility of dry matter(DM), crude protein(CP) and neutral detergent fiber(NDF) in hulled DLRM, dehulled DLRM and dehulled DLRM based diet by pepsin-pancreatin incubation system in vitro. The objective was to screen out the promising enzymes and their appropriate levels for DLRM and DLRM based diet.The results were as follows:1. The enzyme combination of A₃D₂B₁C₄ inclusion in hulled DLRM resulted in the highest digestibility of CP(59.6%) and NDF(21.5%) and a relatively higher DM digestibility(39.8%). The analysis result of variance indicated that cellulase A and xylanase D were the main factors effecting the digestibility of DM, CP and NDF, and no significant effect was observed for xylanases B and C, so the levels of these two enzymes could be freely selected. Weighing the efficacy and cost from enzyme addition, appropriate enzyme combination for hulled DLRM was A3D2, namely, 400g/t cellulase A plus 250g/t xylanase D.2. The enzyme combination of A2D2B3C1 inclusion in dehulled DLRM resulted in the highest digestibility of CP(63.6%) and NDF(10.9%) and a relatively higher DM digestibility(48.7 % ).The analysis result of variance indicated that cellulase A and xylanse D were the main factors effecting the digestibility of DM, CP and NDF, and no significant effect was observed for xylanases B and C, so the levels of these two enzymes could be freely selected. Weighing the efficacy and cost from enzyme addition, appropriate enzyme combination for hulled DLRM was A2D3, namely, 200g/t cellulase A plus 5OOg/t xylanase D.3. The enzyme combination of A2D2B3C1 inclusion in dehulled DLRM based diet resulted in the highest digestibility of CP(68.4%) and NDF(18.8%) and a relatively higher DM digestibility(50.7%).The analysis result of variance indicated that cellulase A and xylanase D were the main factors effecting the digestibility of DM, CP and NDF, and no significant effect was observed for xylanases B and C, so the levels of these two enzymes could be freely selected. Weighing the efficacy and cost from enzyme addition, appropriate enzyme combination for hulled DLRM based diet was A2D2 (special cocktail enzyme) , namely, 200g/t cellulase A plus 25Og/t xylanase D.Experiment 2: two commercial enzyme preparations R(containing cellulase and xylanase activities) and P(containing xylanase, protease and amylase activities) application to pigs were used as the control to investigate the effect of enzymes R, P and "special cocktail enzyme" inclusion in DLRM based diet for growing pigs(27.8kg-67.9kg) on average daily gain(ADG), feed intake and feed conversion ratio(FCR). The objective was to validate and compare the effect of special cocktail enzyme application to DLRM based diet for pigs, and to explore the relationship between the nutrient digestibility and animal performance. The results were as follows:1. Supplemental enzyme R(500g/t), enzyme P(5OOg/t) and "special cocktail enzyme" (450g/t) in dehulled DLRM based diet for growing pigs all resulted in an increase in ADG by 5.5 %, 7.6% and 6.5%(829gAk 846g/d> 837g/d vs 786g/d , PO.05), respectively, in comparison to the control without enzyme addition. Enzymes P(500g/t) and "special cocktail enzyme" (450g/t) addition also resulted in a decrease in FCR by 5.6 % and 7.6% (2.34, 2.31 vs 2.50, PO.05), respectively.2. Supplemental enzyme R(500g/t), enzyme P(500g/t) and "special cocktail enzyme" (450g/t) in dehulled DLRM based diet for growing pigs all significantly(P<0.05) improved apparent fecal digestibility of dry mater, gross energy, crude protein , neutral detergent fibre, acid detergent fibre, and total phosphorus. By "special cocktail enzyme" addition the excreted phosphorus from feces was reduced by 38.7%, 19.1% and 9.6%(P<0.05), compared to the control, enzymes R and P, respectively.Experiment 3: commercial enzyme preparations B(bacterial origin endoxylanase) and D(fungal origin endoxylanase) application to poultry were used as the control to investigate the effect of enzymes Ek D and "special cocktail enzyme" inclusion in diets for broilers on ADG> feed intake and FCR. The objective was to validate and compare the effect of "special cocktail enzyme" application to DLRM based diet for broilers. The result was as follows:1. Supplemental enzyme D and "special cocktail enzyme" in dehulled DLRM based diet for broilers(4-21d) both resulted in an increase in ADG by 7.2% and 5.9% (35.7gA^ 35.4g/d vs 33.3g/d, P<0.05) , respectively, and "special cocktail enzyme" addition also resulted in a reduction in FCR by 7.1 %(1.18 vs 1.27, PO.05). During total experimental phase(4-42d), broilers fed dehulled DLRM based diet supplemented with "special cocktail enzyme" had a numerically improved ADG(52.5g vs 50.6g, P>0.05) and a lowest FCR(1.18) among the experimental groups.The following conclusions can be drawn from all the above results: The feeding value of DLRM could be further improved by using "special cocktail enzyme" to degrade its high dietary fibre. "Special cocktail enzyme" had a similar even better application effect in DLRM based diets for pigs and poultry than commercial enzyme preparations. The in vitro and in vivo studies indicated that the digestibility of DM, CP and NDF could be used as the appropriate parameter to evaluate the effects of enzymes through the in vitro incubation system .