Printer Friendly

Effects of supplementing different levels of a commercial enzyme complex on performance, nutrient availability, enzyme activity and gut morphology of broilers.

ABSTRACT : A trial was conducted to study the influence of different levels of a commercial enzyme complex on performance, nutrient availability, blood parameters, digestive tract measurements, amylase and trypsin activity of the digestive tract and gut morphology in broilers fed the typical diets in north China. There were four treatments: the control diet and the other three enzyme complex supplemented diets which were 180 mg/kg, 360 mg/kg and 720 mg/kg enzyme complex supplemented to the control diet, respectively. The birds fed the diets supplemented with 180 mg/kg and 360 mg/kg enzyme complex had better performance and nutrient availability, the activities of amylase and trypsin in the digestive tract in the two treatments were improved, the villus height and surface area of villus in the small intestine increased and the crypt depth and epithelial thickness of small intestine decreased. Relative weights of pancreas and relative weights and lengths of small intestine decreased. However, the addition of 720 mg/kg enzyme complex had no effects on these parameters and increased crypt depth and epithelial thickness of the small intestine. The data suggested that suitable supplementation of enzyme complex was beneficial for the birds, while excess enzyme complex inhibited secretion of endogenous enzyme and destroyed the structure of the small intestine. (Key Words : Enzyme Complex, Broilers, Performance, Nutrients Utilization, Enzyme Activity, Guts Morphology)

INTRODUCTION

The typical formulation of broiler diets in north China is quite variable and is mainly dependent upon the cost of ingredients; as a result, regional differences in diet formulation, feed quality and broiler performance can be quite dramatic. With increasing feed cost and rapid development of the enzyme industry, use of exogenous enzymes as a cost-effective means of improving feed efficiency, poultry performance and environmental quality is already relatively commonplace. There are diverse benefits to be gained from the use of enzymes in poultry diets. Some of the benefits influencing the performance of poultry are increased feed value of the dietary raw materials, reduction in the variation of nutrient quality of the diet, increased nutrient digestibility, reduction in water content of the excreta (Sarmiento-Franco et al., 2003), reduced viscosity of intestinal contents and the weight of digestive organs and accelerated rate of passage of digesta through the gastrointestinal tract (Lazaro et al., 2004). The efficacy of exogenous enzymes depends on many factors such as the chemical characteristics of the ingredient and diet being evaluated, the microbial population in the gut (and, consequently, the age of the bird), the characteristics and amounts of the enzymes used (Sarmiento-Franco et al., 2003), feeding regimes and feed processing methods, and dietary nutrition levels. Many commercial enzyme additives are mixtures of protease, cellulase and amylase. In this case, protease may attack other enzymes and decrease their efficiency. To be fully functional in the digestive tract, exogenous enzymes should be resistant to attack of protease in the small intestine and able to exhibit catalytic activity in the pH range 6 to 8 (Wang and Hsu, 2006). Although the practical efficacy of supplementing feed enzymes has been well established, the precise mechanism(s) involved and their site(s) of action have been less extensively explored (Silva and Smithard, 2002). Some experiments showed that excess addition of enzyme complex inhibited the secretion of endogenous enzymes (Inborr, 1990; Mahagna et al., 1995) and decreased nutrient digestibility (Ni, 2000). An understanding of the mechanisms of enzyme supplementation will enable optimized supplementation with the required enzyme activity. However, there is no systematic information on the influence of different levels of enzyme supplementation in broiler diets. Therefore, the present study was conducted to investigate the effects of different levels of an exogenous enzyme complex supplemented to typical broiler diets in north China on performance, nutrient availability, blood parameters, amylase and trypsin activity, relative weight or length of digestive tract and gut morphology. Furthermore, we investigated the correlation of exogenous enzyme supplementation with endogenous enzyme secretion.

MATERIALS AND METHODS

Enzyme complex

The enzyme complex used in the present experiment was supplied by Guangdong VTR Bio-tech Co. Ltd., (Zhuhai, China) and contained mainly neutral protease (3,000 U/g), acid protease (3,000 U/g), endoamylase (500,000 U/g) and xylanase (65,000 U/g). It also contained lower amounts of exoamylase, [beta]-glucanase, pectinase, cellulase and cellobiose.

Experiment design and diets

There were four treatments and six replicates per treatment. The basal diet (Table 1) was formulated to meet the requirements recommended by National Research Council (1994) for broilers. Three experimental diets were formulated by supplementing the basal diet ([T.sub.0]) with 180 mg/kg ([T.sub.1]), 360 mg/kg ([T.sub.2]) and 720 mg/kg ([T.sub.3]) of the enzyme complex, respectively. All diets were fed in a mash form.

General procedures

Three hundred and eight-four 21-d-old Avian broilers were obtained from a commercial broiler group and randomly assigned to 24 pens in two-tier cages. All birds received fluorescent lighting throughout the trial.

Body weight and feed intake were obtained for each pen at two-weekly intervals. Birds were allowed to consume feed and water ad libitum during the 28-d trial period. Mortality was recorded daily and feed to gain ratio was corrected for mortality.

Sample collection

During the last week (d 42 to 46), total collection of excreta was carried out for the determination of apparent digestibility of crude protein (APD) and gross energy (AED). Feed intake and excreta were measured by pen over 5 consecutive days. Excreta were pooled within each pen, mixed well using a blender and two representative samples were taken. The samples were freeze-dried. Dried samples were ground to pass through a 0.5 mm sieve and stored in airtight plastic containers at -4[degrees]C until chemical analysis.

On d 49, three birds from each pen with body weights closest to the mean were selected and weighed. Two birds were used for digestive tract measurements and the third for examination of blood parameters and gut morphology. The birds were killed by cervical dislocation and the digestive tract, from the pancreas to ileum, was carefully and swiftly excised. The weight of pancreas was recorded; then the intestinal contents were removed and the weights and lengths of the empty duodenum (pancreatic loop), jejunum (from the pancreatic loop to Meckel's diverticulum) and ileum (from Meckel's diverticulum to ileocaecal junction) were recorded. After weighing, a pancreas sample of about 1 g was taken from the proximal, medial and distal portions of the pancreas and cut into pieces. Pancreas samples (according to W/V = 1/10 (g/ml)) and digesta of duodenum, jejunum and ileum (according to W/V = 1/5) were added into ice-cold deionized water. The mixture was homogenized and centrifuged (13,000 g for 5 min) and the supernatant was transferred into a 2 ml eppendorf tube immediately and frozen at -20[degrees]C until analyzed.

Before the third bird was killed, blood samples were obtained for subsequent determination of blood sugar and urea nitrogen in plasma. Approximately 5 cm lengths of duodenum (midpoint of the pancreatic loop), jejunum (midpoint of jejunum) and ileum (5 cm after Meckel's diverticulum) were removed for measurements of gut morphology.

Intestinal morphology

Examinations of intestinal morphology were carried out according to the method of Iji et al. (2001). Intestine samples from each section were fixed in 10% buffered formalin until analyzed. Each segment was embedded in paraffin. A 7-[micro] m section of each sample was placed onto a glass slide and stained with alcian blue/haematoxylin and eosin for examination with a light microscope. Villus height, crypt depth, the width of the apical and basal part of the villus and the thickness of epithelium and muscle were measured at 100xmagnification using computer software (Sigma Scan, Jandel Scientific, San Rafael, CA, USA), and then the ratio of villus height to crypt depth and villus surface area was calculated.

Chemical analysis

Dry matter (DM) content was determined using standard procedures (AOAC, 1990). DM retention (DMR) was calculated as described by Marquardt et al. (1979). Gross energy was determined using an adiabatic bomb calorimeter (GR-3500 Autobomb, Changsha, China). APD and AED were determined as described by Rotter et al. (1989). The activities of amylase and trypsin of the pancreas and small intestinal digesta were determined using reagent boxes (Jiancheng Bioengineering Institute, Nanjing,China). One amylase unit was the amount of enzyme that hydrolyzed 5 mg starch in 15 min at 37[degrees]C. Trypsin activity was expressed as units per milligram of protein, which was determined by the method of Lowry et al. (1951).

Statistical analysis

For performance and nutrient availability measurements, each pen of birds was considered as an experimental unit for statistical analysis. For digestive tract measurements and gut morphology, the individual bird was considered as an experimental unit. All data were statistically analyzed using the GLM Procedure of SAS (SAS Institute, 1996). The differences between treatment means were considered to be significant at p<0.05.

RESULTS

Bird performance and nutrient availability

Effects of enzyme complex levels on the performance, nutrient availability, livability and fecal moisture of broilers are presented in Table 2. Average weight gain, feed:gain ratio(FCR), DMR, AED, and APD were significantly improved for the birds of [T.sub.1] and [T.sub.2] compared to those of [T.sub.0] and [T.sub.3] (p<0.05).There was no difference in feed intake among the four treatments (p>0.05). All enzyme treatments improved livability and reduced excreta moisture of birds significantly (p<0.05).There were no significant differences in the above parameters between [T.sub.0] and [T.sub.3] (p>0.05).

Weight and length of digestive tract, activity of amylase and trypsin, and blood parameters

The content of blood sugar and the relative activity of amylase and trypsin of the pancreas and small intestine were higher, and blood urea nitrogen content, the relative weight of pancreas and the relative length of jejunum were lower for birds fed [T.sub.1] and [T.sub.2] than for those fed [T.sub.0] and [T.sub.3] (p<0.05) (Table 3). Comparing with the control group ([T.sub.0]), the addition of 720 mg/kg enzyme complex ([T.sub.3]) had no significant effects on blood parameters, relative weight and length of the digestive tract and the relative activities of amylase and trypsin (p>0.05).

Gut morphology

Effects of enzyme complex levels on gut morphology are shown in Table 4. The height and surface area of small intestine and the villus height: crypt depth ratio were increased and the crypt depth of small intestine was decreased by treatment [T.sub.1] and [T.sub.2] (p<0.05). Supplementing 720 mg/kg enzyme complex ([T.sub.3]) increased the crypt depth of duodenum, duodenum muscle thickness and ileum epithelial thickness (p<0.05).There were no significant differences in other gut morphology between treatments [T.sub.0] and [T.sub.3] (p>0.05).

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Figure 1 to 4 showed light micrographs of sections of the duodenum from the four treatments. [T.sub.1] and [T.sub.2] treatments increased height of the villus while the villi were thinner than other groups. However, addition of 720 mg/kg enzyme complex ([T.sub.3]) resulted in shortened, widened and atrophied villi. The changes in length and width of villi in the jejunum and ileum were consistent with changes in the duodenum.

DISCUSSION

The addition of 180 mg/kg and 360 mg/kg enzyme significantly increased weight gain and reduced feed to gain ratio. These results agree with previous research (Pack et al., 1998; Gracia et al., 2003), which reported that supplementing corn-based diets with enzyme produced significant positive responses in growth performance, although the enzyme used in those studies contained predominantly amylase. Early studies also showed beneficial effects of amylase and protease preparations on growth and feed efficiency of chicks when added to diets (Fry et al., 1958; Burnett, 1966). Zanella et al. (1999) found that supplementation of a corn-soybean meal (SBM) diet with a mixture of amylase, protease, and xylanase, similar to our study, did not affect intestinal viscosity and the viscosity was low, so the improvement of performance may not be correlated to intestinal viscosity. Cafe et al. (2002) reported that supplementation of corn-SBM diets with an enzyme complex containing amylase, protease, and xylanase improved body weight gain of male broilers at 16, 35, and 49 d while FCR was worse than the control treatment; this may have been due to the nutritional level which was higher than other studies. Bi Yu and Chung (2004) reported that by lowering the activity of [alpha]-amylase the weight gain of birds at 21 d was lower; when adequate activity of [alpha]-amylase was supplemented along with nonstarch polysaccharide-degrading enzymes, further numerical growth responses were obtained. Mahagna et al. (1995), however, did not find any beneficial effect of enzyme complexes on performance or digestibility of nutrients in broilers from 1 to 14 d of age fed sorghum-SBM diets; this may be correlated to supplementation levels of the enzyme. The activities of enzymes supplemented in our study are much higher than in the study of Bi Yu and Chung (2004). The present study showed that [T.sub.2] treatment did not produce better performance than [T.sub.1], and adding 720 mg/kg enzyme complex ([T.sub.3]) caused no improvements in performance. Similar results were found with wheat-based diets (Iji et al., 2001), on which supplementation of enzyme complex at a low dose was shown to be beneficial in improving bird performance while a high dose had no effect or tended to decrease performance.

[FIGURE 3 OMITTED]

[FIGURE 4 OMITTED]

Digestibility of nutrients in these ingredients was affected by exogenous enzyme supplementation. [T.sub.1] and [T.sub.2] treatments significantly improved DMR, AED and APD. Previous studies have shown that enzyme complex containing amylase, protease, and xylanase, similar to our study, improved the digestibility of starch, DM and energy (Zanella et al., 1999; Bi Yu and Chung, 2004; Scheideler et al., 2005). Bi Yu and Chung (2004) concluded that exogenous enzyme addition appeared to be beneficial for reduced-energy diets. Kocher et al. (2003) reported that combined addition of pectinase, protease, and amylase significantly improved [AME.sub.n] when added to a corn-SBM diet low in energy and protein, whereas addition of the same enzyme combination to a corn-SBM diet with increased energy and protein content resulted in a significant reduction of [AME.sub.n]. Addition of 720 mg/kg enzyme complex ([T.sub.3]) tended to decrease nutrient digestibility. Similar results were found in wheat-based diets (Ni, 2000) for broilers, on which 0.1% enzyme complex increased availability of CP, ME and DM, while 0.23% enzyme complex decreased the availability of CP and DM. This may also be explained similarly to a previous report (Almirall et al., 1995) that opportune exogenous enzyme could increase the activity of endogenous enzymes and interrelating hormones which regulate the endocrine system of the animal body and promote nutrient availability and performance. However, excess exogenous enzymes may inhibit the activity of endogenous digestive enzymes and the secretion of interrelating hormones.

The enzyme treatments significantly reduced excreta moisture of broilers, which is due to enzyme action which releases NSP in diets, disrupts the cell wall matrix and decreases viscosity of digesta. The addition of 360 mg/kg enzyme complex significantly increased livability of broilers which is consistent with published reports (Pack and Bedford, 1997). This may be due to the fact that enzyme complex accelerates the growth of immunity organs of the animal body. Treatments [T.sub.1] and [T.sub.2] significantly increased blood sugar and decreased urea nitrogen, while [T.sub.3] had no effects on blood parameters. This is consistent with previous reports (Borg et al., 1987; Friesen et al., 1992). Friesen et al. (1992) found that enzyme complex increased the digestion rate of starch, while the product of starch digestion was absorbed into blood in the form of glucose and so increased blood sugar content. Borg et al. (1987) reported that blood urea nitrogen could accurately reflect the state of protein metabolism and balance of amino acids, and urea nitrogen was low when the balance of amino acids was good.

Birds fed [T.sub.1] and [T.sub.2] had lower relative weight of pancreas and lower relative weights and lengths of duodenum, jejunum and ileum than other groups, while supplementing with 720 mg/kg enzyme complex ([T.sub.3]) had no effect on the measurements of digestive tract. Onderci et al. (2006) reported that supplementing an amylase-producing culture in broiler diets reduced the relative weight of pancreas. This was in agreement with Wang et al. (2005), who found that enzyme inclusion in wheat-based diets decreased the size of the digestive organs and the gastrointestinal tract to some extent. The relative weight of pancreas has been shown to decrease when an exogenous amylase was supplemented, which indicates that secretion of pancreatic enzymes might be affected by the concentration of enzymes and substrates or products of their hydrolysis in the lumen of the small intestine, which may in turn be due to the reduction of viscosity of the digesta (Brenes et al., 2002). Brenes et al. (1993) reported that 1,000 mg/kg Avizyme SX in barley diets significantly reduced the relative weights of pancreas, duodenum, jejunum and ileum. Cowieson et al. (2003) reported that addition of enzyme in 5 kinds of pea-meal diet caused significant reductions or tended to decrease the relative weights and lengths of small intestine. The reduction in relative weight of digestive tract in treatments [T.sub.1] and [T.sub.2] was also of direct economic benefit, as the dressing yield of broilers should increase proportionally.

Supplementing with 180 mg/kg enzyme complex ([T.sub.1]) had greater effects on digestive enzyme activity of the pancreas, duodenum and ileum than [T.sub.0] and [T.sub.3] treatments, and [T.sub.2] group had higher enzyme activity in the jejunum. This was correlated to performance of the broilers since high enzyme activity accelerates the digestion and absorption of nutrients in the feed. Gracia et al. (2003) concluded that reduction in pancreas weight might have been related to less secretion of endogenous amylase due to the presence of exogenous amylase in the intestine. However, in our study, activities of pancreatic amylase and trypsin increased though the relative organ weight decreased. These results were consistent with a previous report (Inborr, 1990) which concluded that supplementation of higher exogenous protease in diets offered to pigs could disrupt the protein of diets by simultaneously inhibiting secretion of endogenous protease and decomposition of exogenous protease. Mahagna et al. (1995) found that secretion of amylase and protease by the pancreas was reduced when chicks were fed diets supplemented with amylase and protease, which may be due to the fact that excess enzyme was supplemented. Zhengyu Jiang et al. (2008) also showed that the oral administration of different levels of exogenous amylase for broilers affected activities of intestinal enzymes and the production of pancreatic digestive enzymes in a dose-dependent manner. The enzyme activity in the small intestine is composed of exogenous and endogenous enzymes and the enzyme activity of the pancreas is only endogenous. Furthermore, we can conclude that an effective enzyme complex (180 mg/kg and 360 mg/kg) can significantly increase secretion of endogenous enzyme by the pancreas and accelerate the action of exogenous enzyme in the small intestine. However, excess enzyme complex inhibits secretion of endogenous enzymes of the pancreas and impedes the action of exogenous enzyme in the small intestine.

Treatments [T.sub.1] and [T.sub.2] increased villus height, surface area and ratio of villus height to crypt depth of the duodenum, jejunum and ileum. Therefore, improvement in performance of [T.sub.1] and [T.sub.2] treatments may not only be due to the release of simple sugars and protein but also to increased area for absorption of nutrients in small intestine. However, 720 mg/kg enzyme treatment had no effect on these parameters. These results are consistent with the report of Iji et al. (2001) that addition of a high dose of enzyme to wheat-based diets had no effect on villus height, crypt depth or villus surface area in the duodenum, jejunum and ileum of broilers. Reductions of villus height and surface area can reduce the absorption of nutrients. Therefore, the improvement of performance may be also correlated to the small intestine morphology (Onderci et al., 2006).

The enzyme treatments significantly reduced crypt depth of the duodenum, jejunum and ileum and the epithelial thickness of duodenum and jejunum except on the 720 mg/kg treatment. The reduction of epithelial thickness of the small intestine improves absorption by the pillar generative cell. Photomicrographs (Figures 1 to 4) showed that the villus shape in the duodenum of [T.sub.1] and [T.sub.2] groups was longer and thinner than in [T.sub.0] and [T.sub.3] groups, and similar effects were observed in the jejunum and ileum. Jaroni et al. (1999) found that the shortening, thickening and atrophy of the villus in the jejunum of laying hens fed on diets based on wheat middling were reversed with xylanase addition. The enzyme complex in the present study contained xylanase, [beta]-glucanase, cellulase and pectinase. The improvement of small intestine morphology adapted to the increased nutrients in the small intestine.

In conclusion, supplementation of 180 mg/kg and 360 mg/kg enzyme complex improved the performance and nutrient availability, decreased the relative weights and lengths of pancreas, duodenum, jejunum and ileum, improved blood parameters, and increased amylase and trypsin activities of the digestive tract. These supplements were also associated with increased villus height, surface area and decreased crypt depth and epithelial thickness. However, the addition of 720 mg/kg enzyme complex had no beneficial effects on the above parameters. Therefore, excess supplementation of enzyme complex is not beneficial for broilers. There was no significant difference between treatments of 180 mg/kg and 360 mg/kg enzyme complex, so the addition of 180 mg/kg enzyme complex would be recommended to perform most cost effectively under the conditions of this experiment.

ACKNOWLEDGMENTS

This research was supported by a grant from key R&D program of Shaanxi Province (13115 project). The authors express their appreciation to Shenzhen Kondarl (Gaoling) Feed Co. Ltd., and Guangdong VTR Bio-tech Co. Ltd., who partly sponsored this research, and to Dr. C. D. Knight for lingual correction.

Received September 6, 2007; Accepted December 2, 2007

REFERENCES

Almirall, M., M. Francesch, A. M. Perez-Vendrell, B. J. Esteve-Garcia and Enric. 1995. The differences in intestinal viscosity produced by barley and beta-glucanase alter digesta enzyme activities and ileal nutrient digestibilities more in broiler chicks than in cocks. J. Nutr. 125:947-955.

AOAC. 1990. Official Methods of Analysis, 10th Edition. AOAC, Washington, DC.

Bi Yu and T. K. Chung. 2004. Effects of multiple-enzyme mixture on growth performance of broilers fed corn-soybean meal diets. J. Appl. Poult. Res. 13:178-182.

Borg, B. S., G. W. Libal and R. C. Wahlstom. 1987. Tryptophan and threonine requirements of young pigs and their effects on serum calcium, phosphorous and zinc concentrations. J. Anim. Sci. 64:1070-1078.

Brenes, A., M. Smith, W. Guenter and R. R. Marquardt. 1993. Effect of enzyme supplementation on the performance and dige-stive tract size of broiler chickens fed wheat- and barley-based diets. Poult. Sci. 72:1731-1739.

Brenes, A., R. R. Marquardt, W. Guenter and A. Viveros. 2002. Effect of enzyme addition on the performance and gastrointestinal tract size of chicks fed lupin seed and their factions. Poult. Sci. 81:670-678.

Burnett, G. S. 1966. The effect of damaged starch, amylolytic enzymes, and proteolytic enzymes on the utilization of cereals by chickens. Br. Poult. Sci. 3:89-103.

Cafe, M. B., C. A. Borges, C. A. Fritts and P. W. Waldroup. 2002. Avizyme improves performance of broilers fed corn-soybean meal-based diets. J. Appl. Poult. Res. 11:29-33.

Cowieson, A. J., T. Acamovic and M. R. Bedford. 2003. Supplementation of diets containing pea meal with exogenous enzym-es: Effects on weight gain, feed conversion, nutrient digestibility and gross morphology of the gastrointestinal tract of growing broiler chicks. Br. Poult. Sci. 44: 427-437.

Friesen, O. D., W. Guenter, R. R. Marquardt and B. A. Rotter. 1992. The effect of enzyme supplementation on the apparent met-abolizable energy and nutrient digestibility of wheat, barley, oat and rye for the young broiler chick. Poult. Sci. 73:1710-1721.

Fry, R. E., J. B. Allred, L. S. Jensen and J. P. McGinnis. 1958. Influence of enzyme supplementation and water treatment on the nutritional value of different grains for poults. Poult. Sci. 37:372-375.

Gracia, M. I., M. J. Aranibar, R. Lazaro, P. Medel and G. G. Mateos. 2003. [alpha]-Amylase supplementation of broiler diets based on corn. Poult. Sci. 82:436-442.

Iji, P. A., R. J. Hughes, M. Choct and D. R. Tivey. 2001. Intestinal structure and function of broiler chickens on wheat-based diets supplemented with a microbial enzyme. Asian-Aust. J. Anim. Sci. 14:54-60.

Inborr, J. 1990. Enzymes in animal feeding. Milling. 2:28-34.

Jaroni, D., S. E. Scheideler and C. Wyatt. 1999. The effect of dietary wheat middlings and enzyme supplementation. II: apparent nutrient digestibility, digestive tract size, gut viscosity and gut morphology in two strains of Leghorn hens. Poult. Sci. 78:1664-1674.

Kocher, A., M. Chot, G. Ross, J. Broz and T. K. Chung. 2003. Effects of enzyme combinations on apparent metabolizable energy of corn-soybean meal-based diets in broilers. J. Appl. Poult. Res. 12:275-283.

Lazaro, R., M. A. Latorre, P. Medel, M. Gracia and G. G. Mateos. 2004. Feeding regimen and enzyme supplementation to rye-based diets for broilers. Poult. Sci. 83:152-160.

Lowry, O. H., N. R. Rosebrough, A. L. Farr and R. J. Randall. 1951. Protein measurement with the Folin phenol reagent. J. Biol. Chem. 193:265-275.

Mahagna, M., I. Nir, M. Larbier and Z. Nitsan. 1995. Effect of age and exogenous amylase and protease on development of the digestive tract, pancreatic enzyme activities and digestibility of nutrients in young meat-type chicks. Reprod. Nutr. Dev. 35: 201-212.

Marquardt, R. R., A. T. Ward and R. Misir. 1979. The retention of nutrients by chicks fed rye diets supplemented with amino acids and penicillin. Poult. Sci. 58:631-639.

Ni, Z. Y. 2000. Influence of enzyme complex on performance and nutrient availability of broilers. Thesis for Masters Degree Sichuan Agricultural University. Ya'an, Sichuan, China.

NRC. 1994. Nutrient Requirements of Poultry. 9th rev. ed. National Academy Press, Washington, DC.

Onderci, M., N. Sahin, K. Sahin, G. Cikim, A. Aydin, I. Ozercan and S. Aydin. 2006. Efficacy of supplementation of [alpha]-amylase-producing bacterial culture on the performance, nutrient use, and gut morphology of broiler chicken fed a corn-based diet. Poult. Sci. 85:505-510.

Pack, M. and M. R. Bedford. 1997. Feed enzymes for corn-soybean broiler diets. World Poult. 13:87-93.

Pack, M., M. R. Bedford and C. Wyatt. 1998. Feed enzymes may improve corn, sorghum diet. Feedstuffs 2 (Feb.):18-19.

Rotter, B. A., A. A. Frohlich, R. C. Rotter and R. R. Marquardt. 1989. Estimation of the apparent protein digestibility using uric acid corrected nitrogen values in poultry excreta. Poult. Sci. 68:327-329.

Sarmiento-Franco, L., J. M. McNab, A. Pearson and R. Belmar-Casso. 2003. The effects of chaya leaf meal and of exogenous enzymes on amino acid digestibility in broilers. Br. Poult. Sci. 44:458-463.

SAS Institute. 1996. SAS User's Guide: Statistics. Version 7.0. SAS Institute, Cary, NC.

Scheideler, S. E., M. M. Beck, A. Abudabos and C. L. Wyatt. 2005. Multiple-enzyme (avizyme) supplementation of corn-soy-based layer diets. J. Appl. Poult. Res. 14:77-86.

Silva, S. S. P. and R. R. Smithard. 2002. Effect of enzyme supplementation of a rye-based diet on xylanase activity in the small intestine of broilers, on intestinal crypt cell proliferation and on nutrient digestibility and growth performance of the birds. Br. Poult. Sci. 43:274-282.

Wang, H. T. and J. T. Hsu. 2006. Usage of enzyme substrate to protect the activities of cellulose, protease and [alpha]-amylase in simulations of monogastric animal and avian sequential total tract digestion. Asian-Aust. J. Anim. Sci. 19:1164-1173.

Wang, Z. R., S. Y. Qiao, W. Q. Lu and D. F. Li. 2005. Effects of enzyme supplementation on performance, nutrients digestibility, gastrointestinal morphology, and volatile fatty acid profiles in the hindgut of broilers fed wheat-based diets. Poult. Sci. 84:875-881.

Zanella, I., N. K. Sakomura, F. G. Silversides, A. Fiqueirdo and M. Pack. 1999. Effect of enzyme supplementation of broiler diets based on corn and soybeans. Poult. Sci. 78:561-568.

Zhengyu Jiang, Yanmin Zhou, Fuzeng Lu, Zhaoyu Han and Tian Wang. 2008. Effects of different levels of supplementary alpha-amylase on digestive enzyme activities and pancreatic amylase mRNA expression of young broilers. Asian-Aust. J. Anim. Sci. 21:97-102.

Jiu Yuan (1,2), Junhu Yao (1,*), Fengxia Yang (1), Xiaodan Yang (1), Xinjie Wan (3), Jincheng Han (1), Yaojie Wang (3) Xinke Chen (4), Yurui Liu (3), Zhenfeng Zhou (4), Ningbo Zhou3 and Xinyu Feng (4)

* Corresponding Author: Junhu Yao. Tel: +86-029-87092102, Fax: +86-029-87092164, E-mail: yaojunhu2004@sohu.com

(1) Northwest A&F University, Yangling Shaanxi, 712100, China

(2) Gansu Agricultural University, Lanzhou Gansu, 730070, China.

(3) Shenzhen Kondarl (Gaoling) Feed Co.Ltd., Shaanxi Gaoling, 710200, China.

(4) Guangdong VTR Bio-tech Co.Ltd., Guangdong Zhuhai, 519060, China.
Table 1. Ingredients and chemical composition of the basal diet

Ingredients g/kg

Yellow corn 612.90
Soybean meal 138.00
Cotton seed meal 40.00
Corn oil 35.00
Rapeseed meal 30.00
Corn gluten meal 25.00
Meat and bone meal 30.00
Ground limestone 8.00
DDGS (1) 70.00
Methionine 0.80
Lysine-HCl 4.00
Threonine 0.30
Premix (2) 6.00

Chemical composition (3) g/kg

Crude protein 185.00
Calcium 9.40
Total phosphorus 6.30
Available phosphorus 4.30
Lysine 1.00
Methionine 3.80
Met+cys 7.00
Threonine 7.30
AME (MJ/kg) 12.96

(1) Distillers dried grains and solubles produced from corn.

(2) The premix provided per kilogram of diet: vitamin A, 10,000
IU; vitamin D3, 800 IU; vitamin E, 30 IU; menadione, 1.0 mg;
thiamine, 2.0 mg; riboflavin, 5.0 mg; niacin, 50.0 mg; pyridoxine,
5.0 mg; vitamin [B.sub.12], 0.01 mg; pantothenic acid, 10.0 mg;
folic acid, 0.60 mg; biotin, 0.30 mg; iron, 60 mg; zinc, 80 mg;
copper, 10 mg; manganese, 60 mg; iodine, 0.6 mg; and selenium,
0.3 mg.

(3) The value of crude protein and apparent metabolizable energy
(AME) were analyzed.

Table 2. Effects of enzyme levels on performance
and apparent utilization of nutrients of broilers

Parameters [T.sub.0] [T.sub.1] [T.sub.2]

Body weight (g)
 21 d 669.57 673.46 670.25
 35 d 1,344.13 (a) 1,427.88 (b) 1,427.22 (b)
 49 d 2,184.75 (a) 2,288.69 (ab) 2,350.81 (b)

Average daily gain (g)
 22-35 d 48.18 (a) 53.86 (b) 54.22 (b)
 36-49 d 59.88 (a) 66.16 (b) 67.06 (b)
 22-49 d 54.11 (a) 57.69 (ab) 60.02 (b)

Average daily feed intake (g)
 22-35 d 112.51 115.46 114.16
 36-49 d 148.75 149.25 150.33
 22-49 d 129.28 132.87 132.76

Feed to gain ratio
 22-35 d 2.35 (b) 2.15 (a) 2.11 (a)
 36-49 d 2.49 (b) 2.26 (a) 2.24 (a)
 22-49 d 2.42 (b) 2.30 (a) 2.20 (a)
 DMR (%) 64.64 (a) 74.10 (Bb) 71.02 (b)
 AED (%) 64.27 (a) 75.10 (b) 73.95 (b)
 APD (%) 38.18 (Aa) 57.58 (Bb) 50.12 (b)
 Livability (%) 85.40 (a) 91.67 (ab) 95.83 (b)
 Excreta moisture (%) 82.11 (b) 78.43 (a) 79.64 (a)

Parameters [T.sub.3] SEM p value

Body weight (g)
 21 d 674.11 3.70 0.7718
 35 d 1,324.70 (a) 0.027 0.0196
 49 d 2,171.02 (a) 0.041 0.0166

Average daily gain (g)
 22-35 d 46.47 (a) 1.90 0.0140
 36-49 d 59.15 (a) 1.50 0.0016
 22-49 d 53.46 (a) 1.50 0.0141

Average daily feed intake (g)
 22-35 d 109.81 2.30 0.3707
 36-49 d 146.28 3.10 0.8226
 22-49 d 127.45 2.30 0.2972

Feed to gain ratio
 22-35 d 2.39 (b) 0.062 0.0101
 36-49 d 2.48 (b) 0.031 <0.0001
 22-49 d 2.40 (b) 0.033 0.0005
 DMR (%) 62.90 (Aa) 1.90 0.0015
 AED (%) 61.86 (a) 3.30 0.0186
 APD (%) 36.20 (Aa) 3.40 0.0007
 Livability (%) 92.70 (ab) 3.10 0.1416
 Excreta moisture (%) 80.10 (a) 0.55 0.0013

[T.sub.0], [T.sub.1], [T.sub.2] and [T.sub.3] represent basal diets
supplemented with 0, 180 mg/kg, 360 mg/kg, and 720 mg/kg enzyme
complex, respectively. Means in the same row with superscripts of
different lower case and capital letters differ significantly at
p<0.05 and p<0.01, respectively. SEM = Standard error of means.

Table 3. Effects of enzyme levels on relative weight, length and
amylase and trypsin activity of digestive organs and blood parameter
of broilers

Parameters [T.sub.0] [T.sub.1] [T.sub.2]

 Blood sugar (mmol/L) 12.37 (a) 13.43 (b) 13.47 (b)
 Blood Urea nitrogen
 (mmol/L) 0.33 (b) 0.22a (b) 0.18 (a)
Relative weight (g/kg live weight)
 Pancreas 2.66 (Bb) 2.09 (Aa) 2.08 (Aa)
 Duodenum 8.67 (Cc) 6.26 (ab) 5.37 (Aa)
 Jejunum 13.16 (b) 9.87 (a) 9.89 (a)
 Ileum 7.68 (b) 5.72 (a) 5.22 (a)
Relative length (cm/kg live weight)
 Duodenum 15.22 (Bb) 12.58 (a) 11.43 (Aa)
 Jejunum 30.84 (Cc) 24.74 (ab) 23.76 (Ab)
 Ileum 20.28 (b) 18.42 (ab) 16.15 (Aa)
Relative activity of amylase (U/g chyme)
 Pancreas
 (x [10.sup.5] U/g) 15.11 (A) 21.24 (B) 23.62 (B)
 Duodenum 6,687.00 (ab) 12,791.00 (Cc) 10,553.50 (bc)
 Jejunum 1,380.00 (a) 3,016.00 (ab) 4,253.00 (b)
 Ileum 656.50 (a) 2,019.00 (b) 1,699.00 (ab)
Specific activity of trypsin (U/mg protein)
 Pancreas
 (x [10.sup.5] U/g) 472.79 (Aa) 931.35 (Bb) 815.51 (b)
 Duodenum 19,355.76 (Aa) 38,541.33 (Bb) 34,695.81 (b)
 Jejunum 37,095.50 (a) 41,823.54 (ab) 49,515.36 (Bb)
 Ileum 43,113.30 (Aa) 59,313.32 (Bb) 57,026.12 (b)

Parameters [T.sub.3] SEM p value

 Blood sugar (mmol/L) 12.14 (a) 0.30 0.0063
 Blood Urea nitrogen
 (mmol/L) 0.32 (b) 0.04 0.0298
Relative weight (g/kg live weight)
 Pancreas 2.45 (b) 0.10 0.0012
 Duodenum 7.41 (bc) 0.63 0.0081
 Jejunum 11.96 (ab) 0.94 0.055
 Ileum 6.44 (ab) 0.60 0.0472
Relative length (cm/kg live weight)
 Duodenum 13.37 (ab) 0.71 0.0095
 Jejunum 28.54 (bc) 1.54 0.0134
 Ileum 20.52 (Bb) 0.93 0.0117
Relative activity of amylase (U/g chyme)
 Pancreas
 (x [10.sup.5] U/g) 12.73 (A) 1.335 <0.0001
 Duodenum 5,098.50 (Aa) 1,665.00 0.0147
 Jejunum 1,071.50 (a) 750.00 0.024
 Ileum 843.50 (a) 415.00 0.0894
Specific activity of trypsin (U/mg protein)
 Pancreas
 (x [10.sup.5] U/g) 506.01 (Aa) 99.00 0.0077
 Duodenum 21,991.05 (Aa) 3,393.30 0.0013
 Jejunum 35,275.50 (Aa) 3,086.50 0.0179
 Ileum 43,566.94 (Aa) 3,335.40 0.0027

[T.sub.0], [T.sub.1], [T.sub.2] and [T.sub.3] represent basal diets
supplemented with 0, 180 mg/kg, 360 mg/kg, and 720 mg/kg enzyme
complex, respectively. Means in the same row with superscripts of
different small and capital letters differ significantly at p<0.05
and p<0.01, respectively. SEM = Standard error of means.

Table 4. Effect of enzyme levels on the small intestine
morphology of broilers

Parameters [T.sub.0] [T.sub.1]

Duodenum
 Villus height ([micro]m) 1,332.80 (a) 1,635.20 (b)
 Crypt depth ([micro]m) 282.80 (B) 154.00 (A)
 Ratio 4.71 (A) 10.82 (C)
 Surface area ([mm.sup.2]) 3.78 (a) 6.78 (Bb)
 Epithelial thickness ([micro]m) 76.30 (B) 45.85 (A)
 Muscle thickness ([micro]m) 145.60 (Aa) 128.80 (Aa)
Jejunum
 Villus height ([micro]m) 1,020.60 (A) 1,697.50 (Cc)
 Crypt depth ([micro]m) 274.40 (ab) 220.50 (a)
 Ratio 3.93 (A) 7.73 (B)
 Surface area ([mm.sup.2]) 3.11 (Aa) 4.68 (Cc)
 Epithelial thickness ([micro]m) 49.00 (ab) 58.28 (b)
 Muscle thickness ([micro]m) 194.60 182.00
Ileum
 Villus height ([micro]m) 809.20 (a) 938.00 (b)
 Crypt depth ([micro]m) 238.00 (Bb) 168.00 (Aa)
 Ratio 3.63 (A) 5.87 (B)
 Surface area ([mm.sup.2]) 2.04 (ab) 2.49 (bc)
 Epithelial thickness ([micro]m) 45.50 (a) 51.80 (ab)
 Muscle thickness ([micro]m) 193.20 170.80

Parameters [T.sub.2] [T.sub.3]

Duodenum
 Villus height ([micro]m) 1918.00 (Cc) 1,173.20 (Aa)
 Crypt depth ([micro]m) 245.00 (B) 369.60 (C)
 Ratio 8.39 (B) 3.29 (A)
 Surface area ([mm.sup.2]) 5.78 (b) 3.13 (Aa)
 Epithelial thickness ([micro]m) 52.50 (A) 53.20 (A)
 Muscle thickness ([micro]m) 156.80 (a) 189.00 (Bb)
Jejunum
 Villus height ([micro]m) 1,499.40 (Cb) 1,079.68 (A)
 Crypt depth ([micro]m) 226.10 (a) 288.75 (b)
 Ratio 7.08 (B) 3.92 (A)
 Surface area ([mm.sup.2]) 4.09 (bc) 3.43 (ab)
 Epithelial thickness ([micro]m) 44.80 (a) 57.75 (b)
 Muscle thickness ([micro]m) 203.00 222.25
Ileum
 Villus height ([micro]m) 1,040.20 (Bb) 715.40 (Aa)
 Crypt depth ([micro]m) 176.40 (Aa) 193.20 (a)
 Ratio 6.12 (B) 3.73 (A)
 Surface area ([mm.sup.2]) 2.64 (c) 1.97 (a)
 Epithelial thickness ([micro]m) 53.20 (ab) 56.70 (b)
 Muscle thickness ([micro]m) 157.50 172.20

Parameters SEM p value

Duodenum
 Villus height ([micro]m) 84.15 <0.0001
 Crypt depth ([micro]m) 18.80 <0.0001
 Ratio 0.50 <0.0001
 Surface area ([mm.sup.2]) 0.586 0.0002
 Epithelial thickness ([micro]m) 3.62 <0.0001
 Muscle thickness ([micro]m) 9.89 <0.0011
Jejunum
 Villus height ([micro]m) 64.68 <0.0001
 Crypt depth ([micro]m) 18.49 0.0271
 Ratio 0.45 <0.0001
 Surface area ([mm.sup.2]) 0.323 0.0068
 Epithelial thickness ([micro]m) 3.56 0.0255
 Muscle thickness ([micro]m) 17.05 0.4120
Ileum
 Villus height ([micro]m) 38.17 <0.0001
 Crypt depth ([micro]m) 14.35 0.007
 Ratio 0.39 <0.0001
 Surface area ([mm.sup.2]) 0.169 0.0169
 Epithelial thickness ([micro]m) 3.26 0.1233
 Muscle thickness ([micro]m) 15.05 0.4215

{T.sub.0], [T.sub.1], [T.sub.2] and [T.sub.3] represent basal diets
supplemented with 0, 180 mg/kg, 360 mg/kg, and 720 mg/kg enzyme
complex, respectively.

Means in the same row with superscripts of different small and
capital letters differ significantly at p<0.05 and p<0.01,
respectively.

SEM = Standard error of means.
COPYRIGHT 2008 Asian - Australasian Association of Animal Production Societies
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2008 Gale, Cengage Learning. All rights reserved.

 Reader Opinion

Title:

Comment:



 

Article Details
Printer friendly Cite/link Email Feedback
Author:Jiu, Yuan; Junhu, Yao; Fengxia, Yang; Xiaodan, Yang; Xinjie, Wan; Jincheng, Han; Yaojie, Wang; Xinke
Publication:Asian - Australasian Journal of Animal Sciences
Article Type:Report
Geographic Code:9CHIN
Date:May 1, 2008
Words:6658
Previous Article:Effects of dietary copper source and level on performance, carcass characteristics and lipid metabolism in lambs *.
Next Article:Digestibility of amino acids of maize, low tannin sorghum, pearl millet and finger millet in caecectomized roosters.
Topics:


Related Articles
Can exogenous betaine be an effective osmolyte in broiler chicks under water salinity stress?
Effects of replacing soy-oil with soy-lecithin on growth performance, nutrient utilization and serum parameters of broilers fed corn-based diets *.
Effects of different levels of supplementary alpha-amylase on digestive enzyme activities and pancreatic amylase mRNA expression of young broilers *.
Improved broiler chick performance by dietary supplementation of organic zinc sources.
Effects of poultry offal meal and soyabean meal mixtures on the performance and carcass quality of broiler chicks.
The effects of phytase supplementation on performance and phosphorus excretion from broiler chickens fed low phosphorus-containing diets based on...
Nutritional evaluation of full-fat sunflower seed for broiler chickens.
Effects of feed particle size and feed form on growth performance, nutrient metabolizability and intestinal morphology in broiler chickens.
Effect of [beta]-glucosidase as a feed supplementary on the growth performance, digestive enzymes and physiology of broilers.
Effects of Ligustrum lucidum fruits on growth performance, antioxidation and meat quality in arbor acres broilers.

Terms of use | Copyright © 2014 Farlex, Inc. | Feedback | For webmasters