Prediction of ingredient quality and the effect of a combination of xylanase, amylase, protease and phytase in the diets of broiler chicks. 1. Growth performance and digestible nutrient intake

1. A total of 2208 broiler chicks were used in two growth experiments (8 treatments and 12 replicate pens in each experiment) to assess the effects of xylanase, amylase, protease and phytase in maize-based diets. 2. A positive control diet was formulated containing adequate nutrient concentrations. A negative control diet was formulated to contain approximately 628 kJ/kg, 0.13%, 0.12% and 1 to 2% less metabolisable energy (ME), phosphorus (P), calcium (Ca) and amino acids, respectively, than the positive control. In addition, two further negative control diets that contained 167 or 334 kJ/kg more ME, respectively, than negative control 1 were formulated. 3. A further 4 dietary treatments were made by supplementing each of the 4 negative control diets with a combination of xylanase, amylase, protease and phytase, resulting in 8 dietary treatments in a 4 by 2 factorial arrangement. 4. The scale of the removal of energy, P, Ca and amino acids from the positive control diet was determined using least square models based on in vivo data for both the xylanase/amylase/protease cocktail and for phytase and it was predicted that performance of birds fed on negative control 1 would be returned by supplemental enzymes to that of those fed on the positive control. 5. In both experiments there was a significantly poorer performance in birds fed on the negative control 1 than in those fed on the positive control. The poorer weight gain and feed conversion ratio could be attributed in part to a reduced intake of digestible energy, P, nitrogen (N) and amino acids associated with birds fed on the negative control diet. 6. Supplementation of the negative control diets with the enzyme combination returned performance to that of the positive control in both experiments. 7. These data indicate that exogenous xylanase, amylase, protease and phytase can be used successfully in a strategically formulated low nutrient density diet to maintain performance to that of birds fed on a nutritionally adequate diet.     

Energy utilisation of carbohydrate, fat and protein sources in newly hatched broiler chicks

1. TME, TMEn and metabolisability (TME/gross energy) of energy-yielding foodstuffs were determined in 1, 3 and 10 d old broiler chicks, using the assay method developed by Murakami et al. (1994), in order to characterise energy utilisation during the 10 d after hatching. 2. TME, TMEn and metabolisability of dextrin and starch were low in chicks aged 1 d, and increased with age up to 10 d. Energy values of glucose and maltose at days 1 and 3 could not be determined because of the sudden death of birds soon after the feeding. TMEn and metabolisability of cereal sources were lower in d-old chicks than in those aged 3 and 10 d. At all ages, maize was better utilised than wheat and sorghum. 3. In the fat sources (coconut oil, beef tallow and safflower oil) no age dependency was observed in TME, TMEn and metabolisability. 4. Bioavailability of soyabean meal and fish meal was lower at 1 d than at 3 d and 10 d. Energy utilisation from casein was the highest among the protein sources tested and it was not age dependent. 5. It is concluded that energy utilisation of carbohydrate and protein sources during 10 d post-hatch tended to increase with age. Among the energy yielding foodstuffs fat sources seem to be better utilised, with no age dependency.     

Energy utilisation in germ-free and conventional chicks fed diets containing sorbose

1. In experiment 1, growing conventional (CV) chicks were fed on diets containing graded amounts (0, 100, 200 and 300 g/kg diet) of sorbose from 4 to 14 d. Protein, fat and energy deposition were determined after carcase analysis. The values for growth, food efficiency, metabolisable energy (ME) and fat and energy depositions declined as the dietary sorbose content increased. 2. In experiment 2, the performances of germ-free (GF) and CV chicks fed on diets with (100 g sorbose/kg diet) or without sorbose were investigated. On both diets, body weight gain, food consumption and protein accumulation in GF chicks were significantly higher than those in CV birds. No significant differences were observed between the dietary treatment except for ME values, which were significantly lower for the sorbose diet. 3. It is suggested that dietary sorbose decreased energy utilisation, and that the microbial contribution to the utilisation of dietary sorbose was negligible in the chicken.     

Direct-fed microbial and its combination with xylanase,amylase, and protease enzymes in comparison with AGPs on broiler growth performance and foot-pad lesion development

This study evaluated the effect of a direct-fed microbial (DFM) and its combination with xylanase, amylase, and protease (XAP) enzymes cocktail on performance of broilers, in comparison with two commonly used antimicrobial growth promoters (AGPs). Five treatments were tested using day-old Ross 708 broilers (mixed sex at 50:50 ratio) in a completely randomized design with 8 replications per treatment (40 birds/pen) using built up litter. Treatments were 1) a negative control (NC) based on corn/soy/wheat (10%) containing 500FTU/kg phytase, 2) NC + DFM (150,000 CFU/g of 3 Bacillus strains) (DFM150); 3) NC+ DFM (75,000 CFU/g of 3 Bacillus strains) in combination with XAP, XAP + DFM75); 4) NC+ BMD (50 g/ton), and 5) NC+ virginiamycin (20 g/ton). Diets were fed in mash form ad libitum in 3 phases: d 1 to 10 (starter); d 11 to 21 (grower) and d 22 to 42 (finisher). Body weight and feed intake (FI) were measured per phase and feed conversion ratio (FCR) was corrected for mortality weight. Treatment means were compared using a one-way analysis of variance (ANOVA) and separated via Duncan's Multiple Range Test. Supplementation of DFM increased (P < 0.05) average BW at d 10 when compared to the NC. Overall 42-d data indicated that the combination of XAP+DFM75 reduced (P < 0.05) mortality weight corrected FCR compared to NC, both DFM150 and the combination of XAP+DFM75 did not differ from both AGP treatments. Feed intake and body weight gain (BWG) were not affected by treatments during the 42-d study. The combination of XAP+DFM75 also reduced (P < 0.05) foot-pad lesion score as well as improved energy efficiency compared to the NC. These data indicate that both DFM150 and the combination of XAP + DFM75 may be used as an alternative to AGPs to achieve similar growth performance when producing broilers chickens under similar conditions.     

Increased iron level in phytase-supplemented diets reduces performance and nutrient utilisation in broiler chickens

1. The effect of different levels of dietary iron on phytase activity and its subsequent effect on broiler performance were investigated in a 3 × 2 factorial arrangement. A total of 360 day-old Ross 308 male broiler chicks were distributed to 6 experimental diets, formulated with three levels of Fe (60, 80 and 100 mg/kg) and two levels of phytase (0 and 500 FTU/kg).

2. Phytase supplemented to mid-Fe diets increased feed consumption more than the non-supplemented diet at d 24. From hatch to d 35, Fe × phytase interaction significantly influenced the feed intake (FI), body weight gain (BWG) and feed conversion ratio (FCR). The high-Fe diet supplemented with phytase significantly reduced FI and BWG of broilers than those supplemented with low- or mid-Fe diets. The overall FCR was significantly better in birds fed on the mid-Fe diets with phytase supplementation.

3. A significant improvement in ileal digestibility of N, P, Mg and Fe was observed in birds feed diets containing 60 mg Fe/kg, with significant interaction between Fe and phytase.

4. Phytase improved the bone breaking strength when supplemented to low- or mid-Fe diets, compared to the non-supplemented diets. There was a significant Fe × phytase interaction effect. Tibia Fe content was higher in birds fed on phytase-free diets with high Fe but the reverse was the case when phytase was added and their interaction was significant. High dietary Fe significantly increased the accumulation of Fe in liver.

5. Phytase improved Ca-Mg-ATPase, Ca-ATPase and Mg-ATPase activities in jejunum when supplemented to the diet containing 80 mg Fe/kg.

6. This study indicates that high (100 mg/kg) dietary Fe inhibited phytase efficacy and subsequently reduced the overall performance and nutrient utilisation of broilers.     

The effect of flavour on the growth and feed utilisation of broiler chicks

The results of four experiments testing the effect of a flavour made up of ethyl butyrate and other esters, phenylacetic acid and other organic acids, oil of juniper and other essential oils, diacetyl, and maltol on the feed utilisation and growth of broiler chicks to 8 weeks of age have shown small but consistent improvements in feed conversion. This improvement was significant (P>0.05) when the 8‐week results of the four tests were pooled, but were not significant when tested within each experiment. The 4‐week results of the combined experiments indicated a highly significant (P<0.01) improvement in feed utilisation following the use of the flavour.     

Effects of mannanoligosaccharide in broiler chicken diets on growth performance, energy utilisation, nutrient digestibility and intestinal microflora

1. A study was undertaken to evaluate the effects of mannanoligosaccharide (MOS, Bio-MOS, Alltech Inc.) on the growth performance, energy utilisation, nutrient digestibility and intestinal microflora of birds given a sorghum-wheat based diet. Two MOS levels (1 and 2 g/kg) were included in the diet. 2. Inclusion of MOS at both levels in the diet improved the apparent metabolisable energy (AME) values of the diet. However, these effects were not as pronounced as those of zinc bacitracin (ZnB) treatment. Dietary ZnB also significantly improved the net energy value of the diet. No significant differences between the different levels of MOS were noticed in the growth performance, AME and net energy values of the diet. Compared to the negative control, inclusion of 2 g/kg MOS tended to improve feed conversion efficiency (FCE) in the starter phase. 3. Dietary MOS did not affect the apparent total tract digestibility of nutrients compared to the negative control. In contrast, ZnB significantly improved the protein digestibility and tended to increase the starch digestibility. The addition of MOS reduced the concentration of arabinose in the soluble non-starch polysaccharides (NSP) fraction in the excreta of birds; whereas, the concentrations of individual sugars in the insoluble NSP and free sugar fractions were increased by ZnB. 4. A decrease in the populations of lactobacilli and coliforms in the ileal and caecal lumen was observed for MOS and ZnB treatments. Correspondingly, pH and microbial fermentation in the gut was altered. The addition of MOS tended to reduce the coliform load at the gut mucosa. 5. Results from the current study suggest that MOS can improve the apparent energy utilisation of the diet and tend to improve FCE of birds in the first three posthatch weeks, which may be partly related to the modulatory effects of MOS on the gut microflora.     

Effect of whole and demucilaged linseed in broiler chicken diets on digesta viscosity,nutrient utilisation and intestinal microflora

1. A study was undertaken to evaluate the effects of the inclusion of linseed or demucilaged linseed in the diet on the performance, fat and fatty acid digestibilities, metabolisability of gross energy and intestinal microflora. 2. The dietary inclusions were 80 and 160 g/kg for linseed and 160 g/kg for demucilaged linseed. Diets were given to chickens from 1 to 23 d of age. 3. Incorporation of linseed in the diet, particularly at 160 g/kg, depressed weight gain and food utilisation. Digestibility of fat and single fatty acids and dietary metabolisable energy were reduced. 4. Inclusion of linseed in the diet markedly increased the viscosity of ileal digesta. Microbial activity in the ileum and caeca was not greatly affected, but there was a significant increase in the number of lactobacilli. 5. The antinutritional effects caused by feeding linseed were partially overcome by substituting demucilaged linseed for linseed in the diet. 6. Results from the current study suggest that the viscous properties of mucilage are a major factor in the observed antinutritional effects of linseed through increasing intestinal viscosity. Such effects might also be mediated by the gut microflora.     

Effect of inclusion level of linseed on the nutrient utilisation of diets for growing broiler chickens

1. Diets containing linseed at inclusions of 0, 80, 120 and 160 g/kg were evaluated for digestibility of nutrients and AMEn content with male broiler chickens. 2. Increasing the concentration of linseed decreased the retention of nitrogen and the digestibility of amino acids, crude fat and fatty acids of diets. 3. Dietary AMEn (MJ/kg) was also affected by the rate of inclusion of linseed, values decreasing from 14.39 to 12.49. 4. In general, a linear regression model explained the relationship between dietary linseed content and nutritive parameters. However, the quadratic response found for the digestibility of several amino acids and fatty acids indicated a non-additive change in their digestibility. 5. Viscosity ofjejunal digesta was markedly increased by each increment of linseed in the diets. This is attributable to the presence of mucilage in linseed and it might explain many of the results obtained in this study.     

Effects of microbial phytase, produced by solid-state fermentation, on the performance and nutrient utilisation of broilers fed maize- and wheat-based diets

1. The influence of a microbial phytase on the performance, toe ash contents and nutrient utilisation of male broilers fed diets based on maize and wheat was investigated. The experiment was conducted as 2 x 2 x 2 factorial arrangement of treatments. Within the factorial, two diet types (maize-soy or wheat-soy) containing two levels of non-phytate phosphorus (3.0 or 4.5 g/kg) were evaluated and each level of non-phytate phosphorus was supplemented with 0 or 500 PU phytase/kg diet. Each of the 8 dietary treatments were fed to 6 pens of 8 birds from d 1 to 21 post-hatching. 2. Main effects of diet type and phytase were observed for all parameters. Main effect of non-phytate phosphorus was significant only for feed/gain and toe ash contents. Phytase addition improved weight gains irrespective of diet type or non-phytate phosphorus level, but the magnitude of improvement in the phosphorus-deficient wheat-soy diet was greater, resulting in a diet type x non-phytate phosphorus interaction. Responses in toe ash contents were noted only in phosphorus-deficient diets, as indicated by a non-phytate phosphorus x phytase interaction. 3. Phytase addition improved apparent metabolisable energy values of wheat-based diets, but had little effect on the apparent metabolisable energy of maize-based diets as shown by a diet type x phytase interaction. The apparent metabolisable energy was not influenced by dietary non-phytate P. 4. Phytase improved ileal nitrogen digestibility in both diet types, but the responses to added phytase tended to be higher in wheat-based diets, as shown by a diet type x phytase interaction. 5. Increasing the dietary non-phytate phosphorus level reduced phosphorus digestibility and increased excreta phosphorus content. Addition of phytase improved phosphorus digestibility, but the increments were higher in low phosphorus diets resulting in a non-phytate phosphorus x phytase interaction. Phytase addition tended to lower the excreta phosphorus content, but the effects were greater in birds fed low phosphorus diets, as shown by a non-phytate phosphorus x phytase interaction.     

Influence of barley inclusion method and protease supplementation on growth performance,nutrient utilisation,and gastrointestinal tract development in broiler starters

The influence of the method of barley inclusion(fine,coarse and whole barley)in a wheat-based diet and protease supplementation(0 and 0.20 g/kg)on growth performance,nutrient utilisation and gastrointestinal tract development of broilers(d 1 to 21)was evaluated in a 3
2 factorial arrangement.Whole barley(WB)grains were ground in a hammer mill to pass through the screen sizes of 2.5 and 8.0 mm to achieve fine(FB)and coarse(CB)barley particle sizes,respectively.A total of 288,one-day-old male broilers were allotted to 36 cages(6 cages/treatment;8 birds/cage).There was no significant(P>0.05)interaction between barley inclusion method and protease for any growth performance or nutrient utilisation parameters.Birds fed diets containing CB and WB showed higher(P<0.05)weight gain,and digestibility of dry matter,nitrogen,calcium,gross energy,and ileal digestible energy compared to those fed FB diets.Compared to the birds fed FB diets,feed per gain was lower(P<0.05)in birds fed diets made of WB.Fat digestibility of the birds fed CB was higher(P<0.05)than those fed FB and WB birds.Compared to FB and CB diets,inclusion of WB resulted in heavier(P<0.05)gizzards but reduced(P<0.05)gizzard pH.Supplemental protease,however,had no effects(P>0.05)on growth performance and nutrient utilisation,most likely due to the well balanced digestible amino acids and high inherent digestibility of protein in the basal diet,and/or the presence of exogenous carbohydrase and phytase.In conclusion,the present results showed that the inclusion of coarsely ground and whole barley in a wheat-based diet can enhance nutrient and energy utilisation and is beneficial to the growth performance of young broilers.     

Yeast cell wall and live yeast products and their combination in broiler diets formulated with weekly ingredient variations

A 6‐week broiler study was conducted to evaluate whether subjecting the intestinal microflora of broilers to the effect of weekly variations in feed ingredients could be ameliorated by the inclusion of yeast‐derived feed additives: a yeast cell wall extract (YCW), live yeast culture (LY) or their combination (YCW + LY). Recent changes in ingredient prices have motivated producers to formulate diets not necessarily based primarily on corn and soya bean meal. Intestinal microflora in birds can vary significantly based on the ingredient composition of their diet, and the make‐up of the flora can influence overall bird performance. Within the three nutrient phases of this study, birds were fed either a traditional corn–soya ingredient profile or a variable‐ingredient regimen, which had weekly changes in the ingredient composition. There were consistent ameliorative effects of the yeast treatments in both the corn–soya and the variable‐ingredient groups throughout all 6 weeks, with the YCW + LY combination showing a reduced effect when compared to either product fed alone. The effectiveness of YCW and LY on ameliorating the effects of weekly ingredient variations appeared most effective during the starter and grower phases, but was less significant during the sixth week.     

Energy and protein utilisation by broiler chickens fed diets containing cottonseed meal and supplemented with a composite enzyme product

ABSTRACT

1. The present study examined the potential of new-generation microbial enzymes to improve the utilisation of energy and protein of cottonseed meal (CSM)-containing diets, with the aim of increasing its inclusion level in broiler chickens diets.

2. Four hundred and eighty, one-day-old Ross 308 male broilers were used to assess the utilisation of energy and protein by broiler chickens fed diets containing four graded levels of CSM – none, low (4, 8, 12%), medium (5, 10, 15%) or high (6, 12, 18%) in the starter, grower, and finisher phases, respectively, supplemented with 100 mg/kg of a composite enzyme product (xylanase and β-glucanase).

3. Inclusion of CSM improved (P < 0.01) apparent metabolisable energy (AME), with further improvement (P < 0.001) seen in the enzyme-supplemented diets. Inclusion of CSM reduced (P = 0.002) the metabolisable energy intake (MEI), but this was increased (P < 0.05) with enzyme supplementation.

4. Enzyme addition increased (P < 0.001) the net energy of production (NEp), while heat production (HP) decreased (P < 0.001) with CSM inclusion. More energy was retained as fat (P < 0.05) and protein in birds fed diets with the enzyme, but this was reduced (P < 0.029) by CSM.

5. There was an increase (P < 0.05) in efficiencies of ME use for energy, lipid and protein retention, with higher CSM levels. The enzyme improved (P < 0.013) efficiency of ME use for lipid retention.

6. Feeding diets containing CSM to the broilers enhanced (P < 0.05) protein intake (PI) and protein efficiency ratio (PER). Positive effects (P < 0.05) of enzyme were observed on protein gain (PG) and net protein utilisation (NPU).

7. Results obtained from this study suggested that nutrient utilisation of diets containing CSM by broiler chickens can be improved by enzyme supplementation.     

肉仔鸡日粮中锌营养状况评价指标的研究

选用384只1日龄商品代从内公鸡随机分成8个处理组,分别饲喂不添加锌的玉米-豆粕型基础日粮(对照组,舍锌28.37 nag/kg)和在对照组基础日粮中以无机硫酸锌形式添加20、40、60、80、100、120 mg/ks和140 mg/kg锌的试验日粮.试验期7 d.研究日粮中添加不同水平无机锌对内仔鸡生长性能、组织锌含量、含锌酶活性以及含锌蛋白及其基因表达的影响,以考察这些指标对评价肉仔鸡锌营养状况的意义.结果表明:肉仔鸡生长性能未受到添加锌水平的显著影响(P>0.24),而胫骨锌、胰脏锌含量以及胰脏金属硫蛋白(MT)含量及其基因表达受锌水平影响极显著(P<0.01),胫骨锌和胰脏锌含量随锌水平增加呈渐近线趋势变化.胰脏MT含量及其基因表达则呈线性上升趋势.这些指标均可以作为反映肉仔鸡锌营养状况的指标.从相关系数比较来看.胫骨锌和胰脏锌与饲粮锌的相关性比胰脏MT含量及其基因表达更密切.胰脏MT含量及其基因表达随锌水平增加线性上升.可用作评价不同锌源生物学利用率的有效指标.     

Methionine supplementation of low protein diets for broiler chicks in the tropics

1. In the first experiment, diets containing 14, 16, 18, 20, 22 or 24% protein with no methionine supplementation were tested, while in the second experiment diets containing 16, 18 and 20% supplemented with methionine to give 90, 100 or 110% of the recommended N.R.C. levels were compared with an unsupplemented 24% protein diet.

2. Methionine supplementation of the low protein diets stimulated faster gains than the unsupplemented diets but not enough to surpass the response to the 24% protein control diet.

3. It was concluded that a high protein diet unsupplemented with methionine was more economical to feed to broilers than supplemented low protein diets.     

植酸酶和木聚糖酶对断奶仔猪生长性能及蛋白质利用率的影响

本试验研究了在饲粮中添加植酸酶和木聚糖酶对断奶仔猪生长性能及蛋白质利用率的影响。采用完全随机设计．将90头35日龄的断奶仔猪分为5组．每组3个重复．每个重复6头。5个处理组分别为：（1）玉米-豆粕基础日粮（正对照组．PC）,（2）基础日粮-75％磷酸氢钙（负对照组．NC）．（3）负对照组＋植酸酶（植酸酶组,phy）,（4）负对照组＋木聚糖酶（木聚糖酶组,xy）,（5）负对照组＋植酸酶＋木聚糖酶（植酸酶-木聚糖酶组,phy—xy）．植酸酶的添加量为750U／kg,木聚糖酶的添加量为4000U／kg。结果表明：低磷饲粮添加植酸酶或木聚糖酶后．平均日增重和平均日采食量都得到了明显改善（P〈0．05）．植酸酶和木聚糖酶同时添加对仔猪平均日增重的改善极显著（P〈0．01）。在低磷口粮组单独添加植酸酶或同时添加植酸酶和木聚糖酶极显著提高了蛋白质生物学价值（P〈0．01）。饲粮加酶后,血清尿素氮浓度显著降低（P〈0．05）．添加植酸酶或同时添加植酸酶和木聚糖酶后．血清总蛋白浓度显著升高（P〈0．05）．但添加酶对蛋白质表观消化率无显著影响．总之．在断奶仔猪低P日粮中添加植酸酶或木聚糖酶都不同程度地改善了仔猪生长性能．促进了蛋白质的利用．二酶同时添加对仔猪的平均日增重有显著的协同效应．