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1.
1. Two experiments were conducted to evaluate the use of date fibre as a partial replacement of maize as a source of energy for growing broiler chicken. In experiment 1, date fibre was given alone to determine apparent metabolisable energy (AME) and apparent ileal digestibility of amino acids and crude fibre. 2. Date fibre had lower AME content (8.7 vs 13.6 MJ/kg) and apparent ileal digestibility coefficients for dry matter (0.35 vs 0.83), crude fibre (0.20 vs 0.54) and amino acids. 3. Based on the results of experiment 1, a growth study was conducted to test the effect of exogenous enzymes on the nutritive value of date fibre (experiment 2). 4. Three date fibre contents (5, 10 and 15%) with and without enzyme supplementation were evaluated. Daily feed intake, body weight gain and feed conversion ratio were measured. At the end of experiment 2, 160 birds were randomly selected and slaughtered to evaluate carcase and meat quality traits as well as measuring ileal viscosity. 5. Substitution of maize by 10 and 15% date fibre significantly depressed AME. Enzyme supplementation did not improve crude fibre digestibility. The inclusion of date fibre in the diets except at 5% decreased average daily gains, feed intake and feed conversion ratio. 6. Addition of date fibre caused a significant increase in the weights of total digestive tract, pancreas and caecum. Addition of date fibre or the exogenous enzyme had no significant effect on carcase or meat quality characteristics. 7. Date fibre increased ileal digesta viscosity compared to the control. Addition of the exogenous enzyme decreased the viscosity of the basal diets but had no effect on the date fibre diets.8. This study indicated that date fibre can be included at levels of 5% in broiler diets without affecting performance.  相似文献   

2.
An experiment was conducted in a completely randomized design to explore the replacement value of toasted guar meal (TGM) for soybean meal (SBM) in commercial broiler diets. Hypothesis was tested by including graded levels (0, 6, 9, 12, 15, and 18% of diet) of TGM to replace maize-SBM on growth performance, apparent nutrient digestibility, carcass traits, and serum parameters. A total of six iso-nitrogenous and iso-caloric diets were prepared, and each diet was fed ad libitum to 12 replicates of five chicks each from 1 to 42 days of age. Results showed that inclusion of TGM up to 12% in broiler diets did not affect the body weight gain, feed efficiency, and energy digestibility. Feed intake, dry matter, nitrogen digestibility, and relative weights of ready-to-cook yields, breast muscle, abdominal fat, liver, and pancreas were not affected (P > 0.05) by incorporating TGM even up to 18% in broiler diets. Concentration of glucose, total protein, and triglyceride in serum was also not affected (P > 0.05), while serum total cholesterol concentration was found to be higher (P < 0.05) in broilers fed diets containing TGM as compared to those fed on 0% TGM diet. From the results, it was evident that TGM may be incorporated up to 12% in commercial broiler diets for better growth performance, nutrient digestibility, and carcass traits.  相似文献   

3.
Two 18-d studies were conducted to evaluate the effects of drought stress and carbohydrase enzyme inclusion on broiler performance and nutrient digestibility in either yellow dent corn or sorghum. Both experiments employed a 2 × 2 factorial arrangement of treatments with 2 growing environments (normal or stressed), and carbohydrase enzyme cocktail (yes or no). In each experiment, 256 chicks were randomly assigned with 8 birds/pen and 8 replicates/treatment. Enzyme inclusion did not affect any variable in either experiment, and environment did not alter 18-d BW, mortality, or the digestibility of DM or CP. In Experiment 1, birds consuming normal corn had improved FCR compared to those fed drought-affected corn (1.27 vs. 1.33, respectively), which was potentially driven by the difference in apparent total tract digestibility (ATTD) of EE. Alternatively, FCR was not affected by environment in birds fed sorghum-based diets in Experiment 2, but those that consumed normal sorghum had lower feed intake than those fed drought-affected corn (750 vs. 796 g, respectively). In summary, commercial carbohydrase inclusion did not improve growth performance or nutrient digestibility in birds fed normal or drought-affected corn or sorghum. Birds fed drought-affected corn and sorghum affected growth performance variables, but environment did not affect final weight or mortality of broiler chicks.  相似文献   

4.
Three different inclusion levels of a moisture-mold inhibitor mixture (0, 1, and 2%) were added to corn- and soybean-based diets at the mixer as top-dressing additions, and diets were processed at a commercial and a pilot milling facility. Diets were then evaluated according to feed manufacturing variables, pellet quality, broiler performance, and TMEn. Moisture-mold inhibitor additions resulted in an increase in moisture percentages directly after manufacture. After a 2-d storage period, no differences in moisture percentage were detected in diets manufactured at the pilot mill; however, this was not true for diets manufactured commercially. Pellet durability was increased with moisture-mold inhibitor inclusion for the feed processed at the commercial mill, but not for the feed processed at the pilot mill. Relative electrical energy use decreased numerically with increasing levels of moisture-mold inhibitor added to feed processed at the pilot mill. The 1 and 2% diets manufactured commercially resulted in improvements in BW, live weight gain, and FCR, but not the diets manufactured at the pilot mill. There were no differences in TMEn values among treatments, regardless of the manufacturing location. These findings indicate that moisture-mold inhibitor addition has the potential to improve broiler performance and decrease production costs, but improvement depends on the milling technique.  相似文献   

5.
A performance trial was conducted with broiler chicks to study the effect of phytase (PHY) supplementation in diets formulated with reduced AME, Ca, and P. The nutrient digestibility was determined during the 14- to 21-d and 28- to 35-d periods. The treatments consisted of 3 diets (NC1, NC2, NC3) differing in nutrient content and each diet with or without supplemental PHY (NC1, 0 or 500; NC2, 0 or 750; NC3, 0 or 1,000 U of PHY/kg feed) and 1 positive control diet (PC). Compared with the PC diet, negative control diets (NC) resulted in lower AME and apparent ileal amino acid digestibility for some amino acids. Phytase supplementation of the NC diets increased AME, apparent ileal amino acid digestibility, and apparent ileal crude protein digestibility. Phytase addition also increased mineral absorption in 21- and 35-d-old broilers fed NC diets. Reduced nutrient digestibility appears to be a factor in the weight gain and feed intake results. Reducing Ca and P content reduced feed intake in a stepwise fashion in the NC diets. Phytase increased feed intake and generally improved nutrient digestibility, which resulted in an increase in digestible nutrient intake. Averaged across NC diets, PHY improved body weight. Bone-breaking strength was the most consistent predictor of Ca and P reduction. All NC diets had significantly lower bone-breaking strength than the PC. Phytase supplementation of the NC diets gave bone-breaking strengths that were comparable to the PC. Diets with PHY had the highest bioeconomic index.  相似文献   

6.
A review of past literature revealed inconsistencies in recommended grain particle size for optimal broiler performance. Changing diet formulation and subsequent processing variables may alter pellet texture and potentially affect broiler performance. In the current study, ground corn, varying in size (781, 950, 1,042, 1,109, and 2,242 μm), was added to a soybean-based premix to create 5 different mash diets. Water and a commercial pellet binder were added separately to corn-soybean-based diets before steam pelleting to create 2 pelleted diets differing in texture (soft and hard, respectively). The objective was to evaluate corn particle size, pellet texture, and feed form variation of compound diets on 3- to 6-wk broiler performance, nutrient retention, carcass characteristics, TMEn, feed passage time, and particle size preference. Soft and hard pellets had similar pellet durability (90.4 and 86.2%, respectively) and fines (44.5 and 40.3%, respectively). Increasing particle size of mash diets improved nutrient retention. However, broiler performance and energy metabolism were decreased when corn particle size exceeded 1,042 μm. This observation was due, in part, to increased size and maintenance requirement of the gastrointestinal tract. Broilers fed hard pellets (1,856 g of pellet breaking force) had improved nutrient retention, TMEn, and subsequent performance compared with broilers fed soft pellets (1,662 g of pellet breaking force). Pellet texture may affect broilers in a manner similar to particle size.  相似文献   

7.
为研究添加不同复合蛋白酶制剂对肉鸡生长性能、屠宰性能和营养物质利用率的影响,试验选取2592只1日龄罗斯308商品肉仔鸡公雏,随机分为6个处理组,每个处理组12个重复,每个重复36只,饲养密度12只/m^2。处理1组为对照组,不使用酶制剂,日粮蛋白水平相对于营养标准降低了1.5%,处理2~6组在处理1组的基础上添加5种酶制剂,试验期38 d。结果表明:肉鸡13~24日龄,添加不同蛋白酶均在不同程度上有改善肉鸡料重比的趋势(P<0.10),其中T2组效果较佳,料重比改善0.017;其余阶段及全期,不同处理的肉鸡生长性能无显著差异(P>0.05);各处理组之间肉鸡全净膛率、胸肌率、腿肌率、翅重率、腹脂率、肌胃率、腺胃率差异不显著(P>0.05);在低蛋白日粮的基础上添加蛋白酶均可提高肉鸡日粮表观代谢能(AME)、氮校正表观代谢能(AMEn)、能量利用率以及粗蛋白质表观消化率,其中AME分别提高19、33、8、61、51 kcal/kg,能量利用率分别提高1.2%、1.3%、0.5%、2.2%、1.8%,但统计上差异不显著(P>0.05)。综上所述,在本次试验条件下,添加不同外源蛋白酶对肉鸡生长性能和屠宰性能无显著影响,但可在一定程度上提高营养物质利用率,从而降低肉鸡粪便氮排泄量。  相似文献   

8.
Two experiments were conducted to examine the effects of non-starch polysaccharide degrading enzyme on broiler performance and ileal nutrient digestibility in diets containing dried distillers’ grains with solubles, as well as evaluate non-starch polysaccharide degrading enzyme inclusion in low energy diets with dried distillers’ grains with solubles on performance and carcass yield. Experiment 1 was a 4 (dried distillers’ grains with solubles level of 0, 5, 10, and 15%) x 2 (with and without enzyme) factorial design in battery-reared broilers for 21 d; body weights and feed intake were determined weekly. On day 22, ileal contents were collected to determine digestibility of energy and nitrogen. The second experiment was a 48 d floor pen trial utilizing three dietary treatments: positive control, negative control (positive control, negative control less 132 kcal/kg ME), and a negative control + non-starch polysaccharide degrading enzyme inclusion. Diets included dried distillers’ grains with solubles at 2.5 to 10%. In Experiment 1, BW decreased (P < 0.05) with 15% dried distillers’ grains with solubles inclusion as compared to the control. The FCR was also increased (P < 0.05) with 15% dried distillers’ grains with solubles inclusion as compared to all other diets through 14 d. Inclusion of dried distillers’ grains with solubles reduced (P < 0.05) ileal digestible energy at 10 and 15% inclusion and inclusion of non-starch polysaccharide degrading enzyme increased (P < 0.05) ileal digestible energy. Increased energy and nitrogen digestibility coefficients (P < 0.05) were observed at all dried distillers’ grains with solubles inclusion levels with non-starch polysaccharide degrading enzyme inclusion except for the 10% inclusion rate. In Experiment 2, non-starch polysaccharide degrading enzyme in the negative control diet increased BW compared to the negative control at all observed time points at each phase (P < 0.05). Additionally, non-starch polysaccharide degrading enzyme in the negative control diet reduced mortality corrected FCR through the grower phase. Non-starch polysaccharide degrading enzyme inclusion in the negative control diet resulted in comparable live weights, carcass weights, breast filets, and tenders to the positive control diet; however, fat pad was reduced compared to the positive control (P < 0.05). These data confirm that elevated levels of dried distillers’ grains with solubles in starter diets can negatively impact digestibility and performance of broilers and the inclusion of an non-starch polysaccharide degrading enzyme can increase nutrient digestibility and improve broiler performance in low energy dried distillers’ grains with solubles containing diets.  相似文献   

9.
1. A total of 192 male broilers (Cobb 500) were used in a growth and digestibility assay, involving a 2 x 2 factorial arrangement of treatments, to assess the effects of an enzyme cocktail of xylanase, amylase and protease in maize-based diets. 2. The following two diets were formulated: a positive control diet containing adequate nutrient concentrations for broiler starters as per breeder recommendations and a negative control diet to contain approximately 0.63 MJ/kg apparent metabolisable energy (AME) and 3% amino acids less than the positive control. 3. A further two dietary treatments were developed by supplementing each control diet with an enzyme product containing xylanase, amylase and protease. 4. Birds fed on the negative control diet had poorer weight gain and feed efficiency than those given the positive control diet. There was no effect of diet or enzyme on feed intake. The digestibility of nitrogen, calcium, phosphorus and most amino acids were unaffected by dietary nutrient density. 5. Supplementation of both the positive and negative control diets with the enzyme improved weight gain and feed efficiency compared with the unsupplemented diets. In the case of the negative control, supplemental enzyme improved performance to that of the unsupplemented positive control diet. There was no interaction between diet and enzyme for either weight gain or FCR, suggesting similar beneficial responses regardless of the nutrient density of the diet. 6. In both diets, enzyme supplementation improved AME by an average of 3% (0.35 MJ/kg DM) and nitrogen retention by an average of 11.7% (26 g/kg DM intake vs 29 g/kg DM intake). There was no interaction between diet and enzyme for AME or nitrogen retention. 7. Ileal digestibilities of calcium and phosphorus were not influenced by supplemental enzyme, whereas the digestibility of nitrogen and most amino acids was improved by enzyme addition compared with the unsupplemented control diets. There was no interaction between diet and enzyme for the ileal digestibility of nitrogen and amino acids. 8. These data demonstrate that it is possible to improve the nutritional value of a maize/soy-based diet for broiler starters through the use of exogenous enzymes. The nutrient density of the diet does not appear markedly to influence the response to enzyme, offering flexibility in the use of enzymes for maize-based diets. 9. It is concluded that the energy and amino acid values of maize-based diets for broilers can be enhanced by supplementation with an enzyme cocktail of xylanase, amylase and protease, offering potential economic benefits to producers.  相似文献   

10.
An experiment was conducted to evaluate the effect of substituting different levels of hazelnut kernel oil meal (HKM) for soybean meal (SBM) in diets for broiler. A total of 450 one-day-old female Ross 308 broiler chicks were allocated randomly to three treatment groups of 150 birds each in a randomized design. Each treatment group consisted of five replicates each of 30 chicks. All diets (in mash form) were formulated to meet nutrient concentrations recommended for broilers. The experiment lasted for six weeks. In the experiment, an SBM control (SBM) diet was compared to two HKM diets, replacing 50 (50HKM) and 100% (HKM) of SBM protein, respectively. Body weight gain, feed intake and feed conversion ratio of broilers were adversely affected ( P  < 0.05) by the HKM diets at 42 days of age. Broilers fed 50HKM and HKM had growth performances similar ( P  > 0.05). The carcass yield and abdominal fat pads of birds fed diets with SBM were higher ( P  < 0.05) than those of chicks fed the 50HKM and HKM diets. The edible inner organ weight of chicks fed diets with HKM was the heaviest ( P  < 0.05). It is concluded that SBM cannot be replaced even up to 50% with HKM in commercial broiler diet.  相似文献   

11.
Feed constitutes a substantial cost in organic production. Organic poultry may have access to pasture, a nutrient source that has the potential to curtail feed costs. Past research has demonstrated that feed restriction will motivate broilers to forage. Incorporating a nonstarch polysaccharide (NSP) enzyme may enable broilers to better utilize nutrients found in forage. The objective of this study was to examine ways to decrease feed costs by increasing forage intake through dietary energy dilution (7%) and increasing forage digestibility through the incorporation of an exogenous NSP enzyme. The experiment was conducted during the 3-to-8-wk growing phase in spring and summer months on broilers with and without access to pasture. Dietary energy dilution did not result in increased broiler forage intake. During the spring months, NSP enzyme inclusion enhanced performance only when broilers were given access to pasture. Feeding a low-energy diet with NSP enzyme did not enable broilers to overcome a 7% energy dilution. Decreasing energy and subsequent feed cost in organic broiler diets may be possible with energy dilutions less than 7%, depending on forage intake and quality.  相似文献   

12.
The use of subtherapeutic levels of antibiotics in poultry feed improves performance and morbidity in broiler chickens. However, consumer pressure related to the potential development of antibiotic-resistant bacteria has resulted in the development of nonantibiotic feed additives that may also improve broiler performance. Essential oils, organic acids, and phytogenic compounds enhance production of gastric secretions, stimulate blood circulation, and reduce levels of pathogenic bacteria. The objective of the current study was to assess the use of Biostrong 505+ and Biostrong 510 as natural growth promoters in broiler chickens. Assessment was based on the performance and carcass quality of broilers fed either a maximum-yield or a least-cost commercial broiler diet. The maximum-yield diet improved broiler performance and carcass quality. Biostrong 505+ can be used to improve feed conversion and breast yield when incorporated into diets devoid of antibiotics. This improvement in feed conversion and breast yield was accentuated when Biostrong 505+ was used in conjunction with a maximum-yield diet. Biostrong 510 improved feed conversion when used in poultry diets containing antibiotics.  相似文献   

13.
ABSTRACT

1. A 21-d experiment was conducted to investigate the effect of graded inclusions of waxy starch hull-less (WSHL) barley and a multi-component exogenous carbohydrase on the growth performance, nutrient digestibility and intestinal morphometry of broiler chickens. Five levels of WSHL barley inclusion (0, 65, 130, 195 and 260 g/kg) in a wheat-based diet, and two levels of enzyme supplementation (0 and 150 g/tonne of feed) were evaluated in a 5 × 2 factorial arrangement of 10 dietary treatments. All diets were equivalent in metabolisable energy and digestible amino acid content. A total of 400, one-d-old male broilers (five cages/treatment; eight birds/cage) were used in the experiment.

2. Regardless of enzyme supplementation, feed intake declined (P < 0.001) with increasing inclusion of WSHL barley. Increasing levels of WSHL barley (P < 0.001) and supplemental enzyme (P < 0.01) increased gain to feed ratio.

3. Birds fed diets with 0 g/kg WSHL barley showed the lowest (P < 0.001 to 0.01) digestibility for all nutrients except starch. Only starch digestibility was improved (P < 0.05) by enzyme supplementation. The nitrogen-corrected apparent metabolisable energy improved with increasing inclusion of WSHL barley (P < 0.001) and supplemental enzyme (P < 0.001). Increasing inclusion of WSHL barley increased the relative weight of gizzard (P < 0.001) and reduced jejunal digesta viscosity (P < 0.01). Supplemental enzyme (P < 0.001) reduced digesta viscosity.

4. All levels of WSHL barley inclusion improved digestibility of dry matter, nitrogen and fat, whilst energy utilisation improved at inclusions of 130 g/kg WSHL and above, probably due to lowered digesta viscosity and better development of the gizzard. Gain to feed ratio, starch digestibility, energy utilisation and jejunal digesta viscosity can benefit from carbohydrase supplementation in wheat-based diets, regardless of barley inclusion level.  相似文献   

14.
An experiment was conducted to study the effect of different protein meals, with or without enzyme supplementation, on the performance of broilers. A diet based on a combination of protein meals (15% soybean meal, and 5% each of sunflower meal, canola meal, rapeseed meal, and cottonseed meal) was compared with 4 other diets containing 15% soybean meal and 20% of sunflower meal, canola meal, rapeseed meal, or cottonseed meal. Experimental diets were formulated to contain 2,630 kcal of ME/kg and 0.95% digestible lysine, with all other essential amino acids set to meet or exceed the ideal protein ratios. Each diet was fed with or without supplemental exogenous enzyme (Rovabio Excel at 500 g/metric ton of feed) to 6 replicate pens of 50 chicks from 1 to 35 d posthatch as coarse mash. In the cottonseed meal-based diet, supplemental enzyme resulted in high 35-d feed intake and FCR compared with the cottonseed meal-fed groups with no enzyme. There was a significant (P < 0.05) diet × enzyme interaction for 35-d feed intake and FCR. Birds fed the sunflower meal-based diet had significantly (P < 0.05) higher final BW gain and lower FCR as compared with those fed rapeseed meal- or cottonseed meal-based diets, whereas the BW gain of birds fed the rapeseed meal-based diet was significantly (P < 0.05) reduced compared with birds in all other groups. In conclusion, in low-ME broiler diets formulated on a digestible amino acid basis, up to 20% sunflower meal and canola meal can be safely incorporated into the diet. Supplementation of Rovabio failed to exert any positive effect on production parameters when used with diets containing high levels of each of the common protein meals.  相似文献   

15.
1. The potential for the nutritional improvement of pea-based diets by supplementation with a cocktail of exogenous carbohydrases was investigated using growing broiler chicks. 2. Pea meals (grown in the UK) were included in wheat-based diets at 300 g/kg as a partial replacement for an approximately isonitrogenous mixture of wheat and soybean meal. A wheat/soybean meal diet served as a control and each diet was supplemented with a cocktail of alpha-amylase, pectinase and cellulase. The diets were fed to 1-d-old broiler chicks for a period of 21 d. Weight gain and feed conversion were monitored weekly and excreta were collected during the final week in order to determine nutrient digestibility coefficients and metabolisable energy. On d 21, the gastrointestinal (GI) tract was excised and gross morphology measured. 3. Inclusion of pea meal reduced weight gain, feed conversion, nutrient digestibility and also increased the relative sizes of the distal sections of the GI tract. 4. Enzyme addition partially ameliorated the detrimental effects of pea meal inclusion although similar improvements were also noted for birds fed on the control diet. 5. It is concluded that the nutritive value of pea-meal-based diets can be improved by the addition of carbohydrases, and that some pea cultivars show considerable potential as vegetable protein sources for broiler chicks.  相似文献   

16.
ABSTRACT

1. This study was conducted to assess the effects of graded levels of dietary corn resistant starch (RS) on growth performance, carcass traits, nutrient retention, digestive organ index, intestinal morphology, digestive enzyme activities, and mRNA expression of certain nutrient transporters in broiler chickens.

2. A total of 320, 1-d-old Arbor Acres broiler chickens were randomly assigned to five dietary treatments, with eight replicates of eight birds in each. These treatments included one corn-soybean control diet, a corn-soybean based diet containing 20% corn starch, and three diets supplemented with 4%, 8% and 12% RS by replacing corn starch with 6.67%, 13.33% and 20% of Hi-Maize 260® (identified as control, RS1, RS2, RS3 and RS4, respectively). The feeding period lasted 42 days.

3. Performance parameters including feed consumption, feed conversion, body weight gain and percentage of abdominal fat at d 42 of age, nutrient retention (including dry matter, fat, total starch and nitrogen free extract), and apparent metabolisable energy was measured from d 18 to 20 and d 39 to 41 and showed negative linear responses to increasing dietary RS level (P < 0.05). Birds fed the RS3 and RS4 diets showed higher relative weight of duodenum, jejunum and ileum, as well as lower villus height and villus height/crypt depth compared to the control (P < 0.05). The activity of pancreatic trypsin of birds at d 21 and 42 of age decreased linearly in response to the increase of dietary RS level (P < 0.01). There were linear changes in up-regulated mRNA expression of SGLT-1 and down-regulated mRNA expression of GLUT-2 with increasing proportion of RS at d 21 and 42 of age (P < 0.05), respectively.

4. It was concluded that feeding broilers with diets containing higher concentrations of RS impaired the development of small intestine, which resulted in lower apparent total tract retention of nutrients and poorer body weight gain, feed efficiency and carcass traits of broiler chickens.  相似文献   

17.
1. In order to investigate the effects of xylanase, amylase, protease and phytase in the diets of broiler chickens containing graded concentrations of metabolisable energy (ME), two 42-d experiments were conducted using a total of 2208 broiler chicks (8 treatments with 12 replicate pens in each experiment). 2. Four diets including one positive and three negative control diets were used. Three maize/soybean meal-based negative control (NC) diets were formulated to be identical in available phosphorus (P), calcium (Ca) and amino acids but NC1 contained approximately 0.17 MJ/kg less ME than NC2 and approximately 0.34 MJ/kg less ME than NC3. A positive control (PC) was fed for comparison and was formulated to be adequate in all nutrients, providing approximately 0.63 MJ/kg ME, 0.13% available P, 0.12% Ca and 1 to 2% amino acids more than NC1. 3. The reduction in nutrient density between NC1 and PC was determined using ingredient quality models Avichecktrade mark Corn and Phychecktrade mark that can predict the response to exogenous enzymes in maize/soybean meal-based broiler diets. Supplementation of each diet with or without a cocktail of xylanase, amylase, protease and phytase gave a total of 8 dietary treatments in a 4 x 2 factorial arrangement. The same treatments and diet designs were used in both experiments but conducted in different locations using different batches of maize, soybean meal and minor ingredients. 4. In both experiments, digestibility was improved by the addition of exogenous enzymes, particularly those for P, Ca and certain amino acids. In addition, the supplementation of the PC with enzymes elicited a positive response indicating that over-the-top addition of xylanase, amylase, protease and phytase may offer a nutritionally and economically viable alternative to feed cost reduction. 5. It can be concluded that the digestibility of nutrients by broilers fed on maize/soybean meal-based diets can be improved by the use of a combination of xylanase, amylase, protease and phytase.  相似文献   

18.
Three experiments (EXP) were conducted with the objective of evaluating the effects of varying steam conditioning temperatures (CT) and mixer-added fat (MAF) on a practical broiler finisher diet on feed manufacture variables (EXP 1), 28- to 42-d broiler performance (EXP 2), and early skeletal effect using 3-to 21-d broiler performance and tibiae ash measurements and true amino acid digestibility using cecectomized roosters (EXP 3). For all EXP, we used a 3 CT (74, 85, or 96°C) by 2 MAF (low or high) factorial arrangement, resulting in 6 experimental diets. Prior to EXP 2 and 3, all diets were ground to a common crumble size. In EXP 1, increasing both CT and MAF decreased relative electrical energy use at the pellet mill. In EXP 2, feeding finisher diets manufactured utilizing increased CT and decreased MAF to broilers from 28 to 42 d resulted in increased FCR. Also, CT by MAF interactions demonstrated the highest BW gain when birds were fed diets with high MAF, conditioned at 85°C. In EXP 3, feeding diets manufactured in EXP 1 to broilers from 3 to 21 d resulted in no significant effects on live performance variables. However, a significant CT by MAF interaction was observed, where chicks fed diets using low MAF conditioned at 85 and 96°C resulted in incrementally increased percent tibia ash over those with high MAF. In addition, based on true amino acid digestibility data, altering MAF and especially CT can affect the digestibility of several amino acids.  相似文献   

19.
Two experiments were carried out to determine the effect of dietary ascorbic acid supplementation levels on productivity, carcass characteristics, and mortality of indigenous Venda chickens. The first experiment determined the effect of dietary ascorbic acid supplementation levels on productivity and mortality rate of 175 unsexed Venda chickens between 1 and 6 weeks old. The second experiment determined the effect of dietary ascorbic acid supplementation levels on productivity, carcass characteristics, and mortality rate of 140 female Venda chickens between 8 and 13 weeks old. A completely randomized design was used in both experiments. Supplementation of grower diets with ascorbic acid ranged from 0 to 2,000 mg per kg DM feed in both experiments. Levels of ascorbic acid supplementation for optimum feed intake, feed conversion ratio, growth rate, live weight, and breast meat yield were determined using a quadratic equation. The optimal dietary ascorbic acid supplementation levels for feed conversion ratio, growth rate, and live weight of Venda chickens during the starter phase were 1,050, 1,301, and 1,500 mg/kg DM feed, while, at the grower phase, the optimal supplementation levels for feed conversion ratio, growth rate, live weight, and breast meat yield were 1,000, 1,250, 1,482, and 769 mg/kg DM feed, respectively. Results indicate that different levels of ascorbic acid supplementation optimized feed conversion ratio, growth rate, and live weight of Venda chickens at each growth phase. However, levels of ascorbic acid supplementation for optimum feed conversion ratio, growth rate, and live weight were higher than that for breast meat yield. These findings have implications on ration formulation for Venda chickens.  相似文献   

20.
枯草芽孢杆菌制剂对肉鸡生长、胴体和鸡肉品质的影响   总被引：5，自引：0，他引：5  
本文研究了枯草芽孢杆菌制剂对肉鸡生长性能、胴体和鸡肉品质的影响。选用90羽7日龄的肉仔鸡,随机分成3个处理组,每个处理设3个重复。对照1组饲喂基础日粮,对照2组饲喂基础日粮添加0.05%的硫酸新霉素制剂,试验组饲喂基础日粮添加0.1%的枯草芽孢杆菌制剂。试验期35d。试验结果表明:试验组肉鸡的末期平均体重、净增重和日增重均比对照1组高,且差异显著(P<0.05),但均比对照2组低,差异不显著(P>0.05)。试验组鸡的平均采食量均略高于两对照组(P>0.05),试验组的饲料转化率较对照1组提高3.14%,比对照2组低1.59%(P>0.05)。试验组肉鸡胴体品质的各项指标与两对照组相比,除了腿肌重和腿肌率有显著差异外(P<0.05),其余各项指标均无显著差异(P>0.05)。试验组鸡肌肉氨基酸总量、必需氨基酸和鲜味氨基酸含量均高于两对照组。这表明在较高的营养水平条件下添加枯草芽孢杆菌制剂对肉鸡生长具有一定的促进作用,对肉鸡胴体和鸡肉品质无不良影响,可增加鸡肉鲜味。  相似文献   

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