Two hundred one-day old Ven-Cobb commercial broiler chicks were supplemented with the non starch polysaccharide (NSP) hydrolyzing enzymes i.e (xylanase, ß-D-glucanase, cellulase, mannanase and pectinase @ 2400, 4800, 1800, 4800, and 2400 IU/kg (1X concentration) and 4800, 9600, 3600, 9600 and 4800 IU/kg (2X concentration) respectively to the corn + soybean meal based standard as well as basal diets (-100Kcal) respectively. The birds were weighed, wing banded and randomly distributed in to four experimental groups, with ten replicates and five birds in each replicate to assess the effect of the NSP hydrolyzing enzyme combinations on nutrient utilization and economics of broiler production. The results revealed that the supplementation of NSP hydrolyzing enzymes at 1X and 2X concentrations respectively in the standard and basal broiler diets did shown significant differences (P<0.05) with protein and energy utilization. The NSP hydrolyzing enzyme supplemented with standard and basal corn soya diets @ 1X and 2X concentration respectively had evolved as an economical combination for rearing the broilers.
Feed ingredients in poultry ration consist of cereals and vegetable proteins. These ingredients contain between 10-75% of non-starch polysaccharides (NSP) (Chot, 2011).The NSP in cereals form a part of the cell wall structure and in vegetable proteins, especially legumes, play a role as an energy storage material. Chicken having a simple stomach, cannot digest complex nutrients like non-starch polysaccharides (NSP). Supplementation of chicken diet with fiber degrading enzymes is known to enhance utilization of the complex carbohydrate moiety (Choct, 2006). With the continuous increase in world’s population and the decline in its food reserve, a more efficient conversion of by-products, including those rich in NSP, into high quality food is a top priority area of research today. Soybean meal (SBM) is being used as sole protein source in recent years which contains about 20% NSP (Malathi and Devegowda, 2001). Similarly, other major ingredients used in broiler and layer diets i.e. maize and rice bran contains 9 and 25% NSP, respectively (Malathi and Devagowda, 2001) half of which is cellulose (Saunders, 1986). The NSPs are insoluble (cellulose) and soluble (β-glucose, arabinoxylan, arabinogalactose, xyloglucon etc). The soluble NSPs have the property to immobilize water in its matrix by forming loose gel network which is responsible for increased viscosity, there by depressing the digestibility of fats, proteins and starch. These NSPs impair activity of endogenous enzymes by reducing the contact intensity between nutrients and enzymes, which results in sticky and moist droppings. Use of feed enzymes to improve the nutritive value of poultry diets has become common practice in many countries due to use of feed ingredients containing higher proportion of NSP. Hong et al. (2002) found that the use of an enzyme cocktail (Xylanase, amylase and protease) improved the digestibility of corn-soybean based diets in ducks. Using enzymes in poultry diets not only enhance bird performance and feed conversion, but also reduce environmental problems due to reduced concentration of nutrients in excreta. Similarly the other possible benefits are increased accuracy and flexibility in least cost feed formulation and improved well being of the birds.
Materials and Methods
The experiment was conducted on two hundred (200) one day old straight run Ven-Cobb commercial broiler chicks supplemented with the NSP hydrolyzing enzymes viz. xylanase, ß-d-glucanase, cellulase, mannase and pectinase at 1X and 2X concentrations on corn- soybean meal standard and basal diets(-100 Kcal ) Table 1. These pure enzymes were procured from Advanced Bio- Agrotech Limited, Pune, India. The activity of xylanase, ß-d-glucanase, cellulase, mannase and pectinase was 160000, 200000, 1000000, 200000 IU/g, and 150000 IU/g respectively. The birds were weighed, wing banded and randomly distributed in to four experimental groups, with ten replicates and five birds in each replicate (Table 2). All the birds were reared under standard managemental conditions. The details of the ingredient composition for the experimental diets have been given in (Table 3). The data obtained from the experiment were subjected to appropriate statistical analysis using Statistical Package for Social Sciences (SPSS) 15th version and comparison of means was tested using Duncan’s multiple range tests (Duncan’s, 1955).
Table 1: Details of Experimental Diets Broiler Experiment
|Diet||Dietary Group||Metabolizable energy (kcal/kg diet)|
|I||Control Diet without NSP hydrolyzing enzymes||2950||3050||3150|
|II||Control Diet + 1X NSP hydrolyzing enzymes||2950||3050||3150|
|III||Basal Control (-100Kcal) hydrolyzing enzymes||2850||2950||3050|
|IV||Basal Control with + 2X hydrolyzing enzymes||2850||2950||3050|
Table 2: Details of the NSP Hydrolyzing Enzyme Concentrations Selected for Broiler Experiment
|NSPHE Combinations Selected for Standard Corn-Soya and Corn-Soya Basal Diets|
|Percentage of Enzyme||Xylanase (IU/kg)||β-D-glucanase (IU/kg)||Cellulase (IU/kg)||Mannanase (IU/kg)||Pectinase (IU/kg)|
Table 3: Ingredient Composition of Broiler Standard Control Diet and Basal Diet
|Ingredient (g/kg)||Standard Control Diet||Basal Diet|
|Nutrient Composition (Calculated)|
|Available (P) (%)||0.45||0.40||0.38||0.45||0.40||0.38|
1Trace mineral provided per kg diet: manganese, 120mg; Zinc, 80mg; Iron, 25mg; Copper, 10mg; Iodine, 1mg; and Selenium, 0.1mg. 2Vitamin premix provided per kg diet: Vitamin A, 20000IU; Vitamin D3, 3000IU; Vitamin E, 10mg; Vitamin K,2mg; 3 Riboflavin, 25mg; Vitamin B1, 1mg; Vitamin B6, 2mg: vitamin B12, 40mcg and Niacin, 15mg
Results and Discussion
The performance of commercial straight run broiler chicks fed on various levels of NSP hydrolyzing enzymes to the diets containing corn soybean meal based standard (SD) as well as basal diet (BD) was studied in terms of nutrient utilization and economics of broiler production. There were significant (P<0.05) variations in protein utilization among diets. The protein utilization (69.49 %) was significantly higher (P<0.05) in the NSP enzyme supplemented diet @ 1X. The standard control diet (T1) had shown significant difference (P<0.05) in protein utilization (64.46 %) as compared with that of basal diet. The NSP enzyme supplemented diet @ 2X (T4) had shown significantly better protein utilization (63.06%) as compared to the basal diet (59.32 %) (Table 4). The results revealed that the NSPs are responsible for maximum protein utilization from the corn-soy standard as well as basal diet. NSPs @ 1X concentration have played a significant role in improving the protein efficiency when supplemented to corn-soya standard diet. However results reflected that NSPHEs are more effective at higher concentrations when supplemented to corn-soya sub-optimal diets. Similar findings were observed by Song et al., (2010) who reported higher protein availability with supplementation to 0.01% enzyme combination EPG3 (xylanase + beta-glucanase + beta-mannose) and EPG4(xylanase +β-mannanase +cellulase) to low energy wheat based diet compared to normal energy diet. Coweison and Ravindran (2008a) also recorded improved nitrogen retention in low energy diets. Cowieson et al. (2010) reported that a combination of xylanase (16000 IU/kg) and glucanase (30000 IU/kg) both at highest doses of significantly improved (2%) ileal amino acid digestibility compared to that of positive control (P<0.05). Bedford and Morgan (1996) reported that the xylanase supplementation to broiler diets improved the availability of protein. Marsman et al. (1997) reported that supplementation of Neutrase (commercial enzyme containing protease) and Energex to conventional broiler diets improved ileal digestibility of CP. Saleh et al. (2005) observed that crude proteins were significantly improved in pure enzyme mix group. Khan et al. (2006) reported that the apparent digestibility’s of CP and energy were increased (P<0.05) with supplementation of enzymes. Manwar and Mandal (2009) reported significantly (P<0.01) improved digestibility of nitrogen retentions (P<0.05). Song et al. (2010) reported higher protein availability with supplementation to 0.01% enzyme combination, Narasimha et al. (2013a) reported retention of CP was significantly (P<0.05) improved with addition of NSP enzymes along with prebiotics.
However the findings are in contrast with Slominski et al. (2006). Grover et al. (2001) reported that protein efficiency did not differ significantly .Gheisari et al. (2011) also reported that dietary ileal protein digestibility was not affected by inclusion of guar meal at any level. There were significant (P<0.05) variations in energy utilization among diets. The energy utilization (78.90 %) was significantly better (P<0.05) in the NSP hydrolyzing enzyme supplemented standard diet @ 1X compared with that of the standard control diet (75.88 %). The NSP hydrolyzing enzyme supplemented basal diet @ 2X (T4) had shown significantly better energy utilization (74.77%) compared with that of the basal diet (71.39 %) (Table 4).
Table 4: Effect of Supplementation of Non Starch Polysaccharide Hydrolyzing Enzymes to Corn Soybean Meal Basal Diets on Protein and Energy Utilization (%) in Broilers
|Treatments||Enzymes||Protein %||Energy %|
|T2||SD + 1X HC||69.49a||78.90a|
|T3 ( BD)||0||59.32d||71.39d|
|T4||BD + 2X HC||63.06c||74.77c|
Values bearing different superscripts within a column are significantly (P<0.05) different
The NSPs have positive impact on the energy efficiency of the standard corn-soya as well as corn-soya basal diets. This may be due to NSPs are responsible for breaking down the complex carbohydrate structure of the NSPs and thus making them available in the simpler forms to be utilized by the broilers. These findings are supported by Coweison and Ravindran (2008a) who found that the low nutrient density diets based on corn soy bean meal irrespective of nutrient density, improved AME. Swift et al. (1996), Gracia et al. (1997) and Ravindran et al. (1999) who reported that the supplementation of xylanase and phytase had synergistic effects with respect to increasing AME. Chesson (2001) reported that addition of NSP hydrolyzing enzymes to cereal based diets in poultry restored ME content which was not available due to NSPs. Khan et al. (2006) and Slominski et al. (2006) reported efficiency of energy utilization was better in birds fed on enzyme supplemented diets. Coweison and Ravindran (2008a) observed improved AME. Manwar and Mandal (2009) and Narasimha et al. (2013a) also reported similar findings with addition of NSP hydrolyzing enzymes. Nikam and Reddy (2016) also concluded that the supplementation of NSP hydrolyzing enzymes to the corn-soybean meal based diets has shown significant differences in nutrient utilization. However the findings are not in agreement with Mirakzehi et al. (2010) who reported that TME of all RSM enzyme treated groups were similar to untreated RSM. The significant improvement in GE digestibility observed for broilers fed the corn-SBM diets could result mainly from the disruption of the cell wall matrix of SBM, leading to the release of structural starch and protein (Yu and Chung, 2004). The cost per kg live weight gain of the broilers was calculated by the same method as like the experiment I. The total input cost per kg live weight gain for treatments T1 to T4 were (Rs) 66.17, 62.82, 64.12, and 59.78 respectively. The cost of production per kg live weight gain was lowest in treatment T4 Rs 59.78, diet supplemented with 2X NSP hydrolyzing enzyme and 1X (Rs) 62.82 respectively (Table 5).
Table 5: Cost/Kg live weight gain of broiler fed on corn soybean meal standard and Basal Diets Supplemented with NSPHE at 42nd Day of Age
|Chick cost (Rs.)||24||24||24||24|
|Pre Starter feed intake/bird (g)||481.9||467.4||468.8||450.2|
|Starter feed intake/bird (g)||1350||1393.2||1553.8||1333.6|
|Finisher feed intake/bird (g)||1932||1777.4||2059||1875.2|
|Pre Starter feed cost (Rs.)/kg||27.65||27.65||26.87||26.87|
|Starter feed cost (Rs.)/kg||26.51||26.51||25.92||25.92|
|Finisher feed cost (Rs.)/kg||33.65||33.65||28.35||28.35|
|Total Pre Starter feed cost /bird (Rs.)||13.32||12.92||12.60||12.10|
|Total Starter feed cost/bird (Rs.)||35.79||36.93||40.27||34.57|
|Total finisher feed cost /bird (Rs.)||65.01||59.81||58.37||53.16|
|Total feed cost/bird||114.12||109.67||111.24||99.83|
|Cost of NSP, hydrolyzing enzymes (Rs)||0.00||0.80||0.00||1.60|
|Total input cost (Rs.)/Bird||142.12||138.47||139.24||129.43|
|Total input cost (Rs.)/kg live BWG||66.17||62.82||64.12||59.78|
|Live body weight gain (g) at 42 d||2147.8||2204.3||2171.6||2165.1|
|Sale rate/kg live weight||67.00||67.00||67.00||67.00|
|Difference in total input cost over control||+0.83||+3.36||+2.05||+6.39|
The NSP hydrolyzing enzyme supplemented diets @ 1X (T2) and 2X (T4) has evolved as an economical combination for the broiler feeding when reared on standard as well as basal diets .However the cost of production per kg live weight gain will be higher and will not be economical when broiler standard and basal diets were not supplemented with the NSP hydrolyzing enzymes. The results are in accordance with Augelovicova and Michalik, (1997), Morkanas et al. (1993), Edwin et al. (2004) and Khan et al. (2006) also reported that feed cost was reduced by enzyme supplementation. Cowieson and Ravindran (2008b), Ramesh and Chandrashekaran (2011a) also reported that low calorie and low protein supplemented with exogenous enzymes reduced the feed cost per kg weight gain. Narasimha et al. (2013a) concluded that supplementing sub-optimal energy diets with NSP enzymes along with synbiotics and phytase reduced the cost of production considerably. Nikam and Reddy (2016) also concluded that the supplementation of NSP hydrolyzing enzymes to the corn-soybean based diets was found to be economically viable.
** Part of PhD thesis submitted to Sri Venkateswara Veterinary University, Tirupati – 517502, Andhra Pradesh, India.