不同比例小麦日粮添加木聚糖酶对肉鸡生产牲能的影响

小麦是一种品质较好的能量饲料原料,小麦作为饲料的优点是其蛋白质和赖氨酸含量比玉米高30%～50%,与家畜生长发育密切相关的烟酸含量是玉米的2倍多,Ca、P、蛋氨酸和胱氨酸的含量也比玉米高.但代谢能是玉米的90%左右(NRC,1994),叶黄素、生物素的含量比较低.     

Effect of diet form and enzyme supplementation on growth, efficiency and energy utilisation of wheat-based diets for broilers

1. The effect of diet form (mash, cold-pelleted, steam-conditioned/pelleted, wet mash, whole wheat with balancer pellet, restricted pellet) and enzyme inclusion (Avizyme 1300, absent, present) was studied in 2 trials using individually caged, male broilers from 14 to 42 d. Bird performance, viscosity of ileal contents and diet metabolisability (AME) were measured. 2. The performance of mash-fed birds was significantly poorer than for the other treatments in relation to dry matter intake, liveweight gain and gain:food. This was not due to reduced diet AME content. 3. There was no significant effect of heat treatment on any of the variables measured, although viscosity of ileal contents was increased by 30% as compared to the cold-pelleted diet. 4. Gain:food was improved with wet-mash feeding in comparison to the dry mash treatment but it was concluded that this was not due to any intrinsic improvement in diet quality, but rather to voluntary food restriction on introduction of the wet food. 5. Whole wheat feeding improved gain:food and diet AME content by 3% as compared to the complete diets and caused approximately a 50% increase in gizzard weight as compared with the pelleted diets. 6. Food enzyme inclusion did not improve performance although a significant improvement in diet AME content was observed with enzyme inclusion in trial 1.     

小麦型日粮中添加限制性酶对肉鸡生长性能和胃肠道发育的影响

文章旨在研究小麦型日粮中添加木聚糖酶对肉鸡生长性能和胃肠道发育的影响。试验选择健康、平均体重一致的1日龄肉仔鸡800只,随机分为5组,每组5个重复,每个重复32只。共开展两个试验,试验1共5种日粮:对照组(小麦型1～28 d),处理1(小麦型日粮+0.3 g/kg木聚糖酶21～28 d),处理2(小麦型日粮+0.3 g/kg木聚糖酶14～28 d),处理3(小麦型日粮+0.3 g/kg木聚糖酶7～28 d),处理4(小麦型日粮+0.3 g/kg木聚糖酶1～28 d);试验2同样5种日粮:对照组(小麦型1～36 d),处理1(小麦型日粮+0.3 g/kg木聚糖酶27～36 d),处理2(小麦型日粮+0.3 g/kg木聚糖酶18～36 d),处理3(小麦型日粮+0.3 g/kg木聚糖酶9～36 d),处理4(小麦型日粮+0.3 g/kg木聚糖酶1～36 d)。结果显示:1～28 d肉鸡饲喂添加木聚糖日粮较未添加组和21～28 d显著提高了肉鸡的末重(P <0.05);与对照组相比,各处理组在15～21 d,22～28 d和1～28 d料重比均表现为显著降低(P <0.05)。1～36 d肉鸡日粮添加木聚糖酶较对照组(无酶)或27～36 d组显著提高了肉鸡末重(P <0.05);试验期间(1～36 d)添加木聚糖酶较对照组和27～36 d添加木聚糖酶组显著降低了料重比(P <0.05)。1～36 d肉鸡日粮添加木聚糖酶较对照组显著降低了回肠内容物黏度(P <0.05)。结论 :在小麦型日粮中添加木聚糖酶可以有效促进肉鸡生长后期的生长,而整个试验期不需要一直添加木聚糖酶。     

Effects of dietary fat type and non-starch-polysaccharide-hydrolysing enzyme addition to rye-based diets on muscle protein turnover in broilers

1. Muscle protein turnover was measured in broilers fed on rye-based diets containing either beef tallow (T) or soybean oil (S) at an inclusion rate of 100 g/kg. Each of these diet types was tested either in the absence (S[-], T[-]) or presence (S[+], T[+]) of a xylanase-containing enzyme preparation. Protein turnover was measured in gastrocnemius muscle (GM) and pectoralis major muscle (PM). 2. Fractional rate of protein synthesis (FSR) was measured by the large dose technique using [15N]-labelled phenylalanine whereas fractional protein growth rate (FGR) was estimated by regressing tissue protein content over time. Fractional breakdown rates (FBR) were calculated by the difference between FSR and FGR. 3. In PM, FSR (%/d) was 22.1, 23.4, 21.5 and 24.4 in groups S[-], S[+], T[-] and T[+], respectively, and FBR (%/d) was 8.3, 9.8, 4.5 and 10.8 with the xylanase effect being significant. The FGR of 17.0%/d calculated for the broilers fed on the T[-] diet tended to be higher than for the other groups (13.6 to 13.8%/d). No significant effects were detected for these parameters in the GM. 4. The absolute amounts of protein which were synthesised daily and accreted in both muscles were significantly higher with xylanase supplementation in both fat type diets but at a significantly higher level when soybean oil was the dietary fat type. 5. The observed effects on protein turnover have to be seen in the context of an overall adverse effect of dietary soluble pentosans from rye in combination with tallow on physico-chemical chyme conditions, digestion and absorption of energy and nutrients and tissue-specific metabolic changes.     

Nitrogen metabolism and growth performance of gilts fed standard corn-soybean meal diets or low-crude protein,amino acid-supplemented diets

Two experiments were conducted to determine the CP concentration below which N retention and growth performance are reduced when low-protein, amino acid-supplemented, corn-soybean meal diets are fed. In a N balance trial (Exp. 1), 12 gilts (initial weight 41 kg) were fitted with urinary catheters and fed six different diets during three 7-d periods in an incomplete block design. The diets were: 1) 18% CP; 2) 14% CP + AA, 3) 16% CP; 4) 12% CP + AA; 5) 14% CP; and 6) 10% CP + AA. Amino acids (lysine, threonine, tryptophan, and methionine) were supplemented such that the concentrations in the low-protein diets were equal to those in their standard (4% CP higher) counterparts. Nitrogen retention (g/d) decreased (P < 0.01) as CP decreased, in both standard (27.10, 24.53, and 20.99) and low-protein (21.51, 19.18, and 15.83) diets, but was lower (P < 0.01) in low-protein diets. There were no differences among treatments (P > 0.05) in biological value (68.2% standard vs 71.0% low-protein). In a growth performance trial (Exp. 2), 36 gilts (initial weight 19.5 kg) were penned individually and fed one of six diets for 35 d in a randomized complete block design. Dietary treatments were a 16% CP standard diet and low-protein diets formulated to contain 15, 14, 13, 12, and 11% CP supplemented with crystalline lysine, tryptophan, threonine, and methionine to equal the total concentrations in the standard diet. Protein concentration affected (P < or = 0.05) ADG, ADFI, feed efficiency, fat-free lean gain, longissimus muscle area, plasma urea, and plasma concentrations of most essential AA. For most of these traits, the major difference was poor performance of pigs fed the 11% CP diet. Thus, in Exp. 1, at AA concentrations from deficient to excess, low-protein, amino acid-supplemented diets failed to produce the same N retention as the equivalent corn-soybean meal diets. However in Exp. 2, the same performance was obtained with 16, 15, 14, 13, and 12% CP. Based on these data, we suggest that N balance is more sensitive than growth to amino acid adequacy andthat other AA (e.g., isoleucine and valine) may limit growth performance when the protein concentration is reduced by more than four percentage units.     

Effect of rice polishing and phytase supplementation in diets on productive behavior of broilers

The addition of rice polishing (RP) and phytase enzyme to poultry diets was tested on 200 1-day-old broilers weighing 42 g. Birds were assigned to a completely random design with a 2?×?2 factorial arrangement with four treatments and five repetitions of ten birds each. The factors evaluated were RP level (0 and 15 %) and phytase (0 and 150 g/ton). The trial was divided in two phases of 21 days each (42 days total). In phase 1, no treatment effects were observed (P?>?0.10) on poultry productive behavior. In the second phase (21 to 42 days) and on the total trial (1 to 42 days), there were no effects of the treatments on weight gain or feed intake (P?>?0.10). Feed conversion was affected by RP (P?<?0.01) but not by phytase addition (P?>?0.10). In conclusion, phytase did not affect broiler production with or without RP. Addition of 15 % RP in poultry diets represents an alternative to reduce feed costs.     

饲粮中小麦比例与复合酶添加量对肉鸭生产性能的影响

小麦具有营养价值高、制粒品质好、易于储存和价格偏低的优点,但因含有抗营养因子可溶性非淀粉多糖(SNSP) ,限制了其在配合饲料中的用量(Choct,1 990 ;Bedford ,1 995、1 999;Hew -Lap -Im ,1 999;Krzysztof,1 999)。复合酶制剂在畜禽饲料中的应用,为解决小麦等日粮中的抗营养因子提供了有效途径,但对鸭的研究仅局限在单因素的对照试验。本试验选用含纤维素酶、β-葡聚糖酶、木聚糖酶和果胶酶的复合酶与日粮中含小麦比例两因素,采用2×3试验设计,探讨小麦与复合酶的互作对肉鸭生产性能的影响。1　材料与方法1 1　试验日粮　本试验根据…     

Effect of different dietary protein levels and amino acids supplementation patterns on growth performance,carcass characteristics and nitrogen excretion in growing-finishing pigs

Background: This study was conducted to determine the effects of different dietary protein levels and amino acids supplementation patterns in low protein diets on the growth performance, carcass characteristics and nitrogen excretion in growing-finishing pigs.Forty-two barrows(25.00 ± 0.39 kg) were randomly assigned to 7 diets. Diet 1: the high crude protein diet with balanced for 10 essential amino acids(EAAs). Diet 2: the medium crude protein diet with 2%(approx) decreased protein level of Diet 1 and balanced 10 EAAs. Diet 3: the low crude protein diet with 4% decreased protein level of Diet 1 and balanced 10 EAAs. The protein levels of Diet 4, 5, 6 and 7 were the same as that of Diet 3. Diet 4 was only balanced for lysine(Lys), methionine(Met), threonine(Thr) and tryptophan(Trp); Diet 5 and 6 were further supplemented with extra isoleucine(Ile) or valine(Val), respectively; Diet 7 was further supplemented with extra Ile + Val.Results: Over the 112 days trial, the reduction of dietary protein by 2% or 4% with balanced10 EAAs significantly decreased nitrogen excretion(P 0.05), but had no effects on growth performance and carcass characteristics(P 0.05). In low protein diet, Val supplementation significantly increased body weight gain at 25–50 kg phase(P 0.05), while Ile supplementation at 75–100 kg phase and 100–125 kg phase significantly reduced the ratio of feed to gain(P 0.05). No effect of different dietary protein levels and amino acids supplementation patterns in low protein diets on carcass characteristics was observed(P 0.05). The total N excretion of pigs supplemented with only Lys, Met, Thr and Trp was numerically higher than that of pigs fed with extra Ile, or Val, or Ile + Val diets.Conclusion: In low protein diet, Val is more required than Ile in the early growing phage(25–50 kg), while Ile becomes more required in the late growing and finishing phage(75–125 kg).     

Effect of wheat content, fat source and enzyme supplementation on diet metabolisability and broiler performance.

1. A 3x3x2 factorial experiment studied the interactions of fat source (tallow, soya, tallow:soya [2:1] blend), wheat level (700, 350, 0 g/kg) and enzyme inclusion (Avizyme 1300, absent, present) in diets for broilers fed ad libitum in individual cages from 7 to 35d. Bird performance, fat digestibility, viscosity of ileal contents and diet metabolisability (AME) were measured. 2. There were no significant effects of fat source on bird performance. However, there was a significant effect on fat digestibility, which was highest for soya and lowest for tallow. Diet AME content was also significantly affected by fat source and reflected differences in fat digestibility. 3. Dry matter (DM) intake, liveweight gain (LWG) and gain:food were all reduced at 700 g wheat/kg. Viscosity of ileal contents increased with increasing wheat inclusion. 4. There were no significant effects of enzyme on DM intake or LWG but gain:food was improved by 2%. Diet AME content was increased with enzyme addition, the effect being greatest (9%) with tallow at 700 g wheat/kg. 5. Viscosity of ileal contents was reduced and fat digestibility increased with enzyme addition and there were significant wheat enzyme interactions attributable to no differences with zero wheat but marked responses to enzyme at 700 g wheat/kg. 6. The results confirm important interactions between wheat content and fat composition in relation to fat digestibility, AME content and food efficiency.     

Effects of dietary fat type and xylanase supplementation in rye containing diets on energy metabolism in male broilers

Xylanase supplementation of rye-based diets which contained 10% beef tallow was shown to markedly improve the digestibility of fat whereas the enzyme effect in diets containing 10% soya oil was much less pronounced (Dänicke et al. 1997b). Such interactions between fat type and xylanase supplementation have also been reported for wheat–rye-based diets (Langhout et al. 1997) and wheat-based diets (Allen et al. 1997) and were attributed mainly to the fatty acid composition of different types of fat and to changes in digesta viscosity caused by soluble pentosan. The apparent metabolizable energy, N-corrected (AME_N) contents of such diets were affected in a similar manner suggesting that energy metabolism is also influenced by xylanase supplementation and the type of dietary fat. However, changes in the metabolizability of gross energy does not necessarily indicate whether the efficiency of metabolizable energy (ME) for energy gain is changed nor if different proportions of ME are used for maintaining an energy equilibrium, i.e. ME maintenance requirement. In addition, studies suggest that both dietary fat level and fat type might exert effects on the efficiency of utilization of ME for energy retention (Carew and Hill 1964; de Groote et al. 1971; Fuller and Rendon 1979; Brue and Latshaw 1985). Hence, the aim of this study was to investigate the partitioning of ME between maintenance needs and energy retained as protein and as fat when feeding rye-based diets. The diets contained either soya oil or beef tallow and were either unsupplemented or xylanase-supplemented.     

Effects of sources of protein and enzyme supplementation on protein digestibility and chyme characteristics in broilers

1. The purpose of this study was to evaluate the effects of protein source and enzyme supplementation on protein digestibility and chyme characteristics in broilers. 2. One hundred and twenty growing (13 d old) and 60 finishing (34 d old) Arbor Acre strain commercial male broilers were selected and placed into individual metabolic cages. 3. The experiment was a 5 x 2 factorial arrangement with 5 different sources of protein: casein, fish meal, soybean meal (SBM), soy protein concentrate (SPC), maize gluten meal (MGM) and two levels of protease (bromelain), 0 and 65 CDU/kg diets. 4. The diets were iso-nitrogenous and semi-purified, with Cr2O3 as an indicator for determination of ileal digestibility and chyme characteristics. 5. Apparent ileal protein digestibility (AIPD) in both growing and finishing chickens was highest on the casein diet, followed by fish meal, SBM, SPC and MGM. 6. Enzyme inclusion did not improve protein digestibility, but significantly decreased the digesta pH value in the gizzard and increased pH in the ileum in the 3-week-old broilers. 7. The digesta pH values in the gizzard and duodenum were significantly lower in the SBM and fish meal groups compared with the other protein groups. The molecular weight distribution pattern of the soluble protein in the chyme of the gastrointestinal (GI) segments showed a similar trend, regardless of the enzyme inclusion or the stage of growth. 8. The molecular weight profile of soluble protein changed dynamically in the casein fed broilers from the gizzard to ileum and the low molecular weight proteins, < 7 kDa, reached maximum levels at the ileum. The molecular weight profile of the soluble protein in the SBM and SPC changed between the jejunum and the ileum and in the intermediate molecular soluble protein weight (7 to 10 kDa) was significantly decreased. This indicated that the hydrolysis process began from the middle to the posterior end of the small intestine. 9. Similar profiles were also shown with fish meal protein. The pattern of distribution, however, did not show any prominent change in the GI segments of the MGM group. 10. The pepsin, trypsin and chymotrypsin protease activity in the gizzard and duodenum were highest in the casein group and lowest in the MGM group as compared with the other protein groups. 11. The rate change in the patterns of molecular weight distribution in soluble protein and the digestive enzyme activity provide indications of the partial digestibility of different protein sources. The exogenous enzyme, bromelain, did not show any beneficial effect on protein digestion.     

低营养水平日粮添加酶制剂对肉鸭生产性能的应用效果研究

选用1200羽0日龄的克里莫肉鸭，依性别随机分为3组，每组设4个重复，每个重复100羽，公母各半，Ⅰ组为对照组，饲喂基础日粮，Ⅱ组和Ⅲ组为试验组，在基础日粮中分别添加0．10％的国外品牌PS酶和0．10％的国内品牌酶。试验结果表明：2种酶制剂可显著地提高肉鸭的日增重（P〈0．01），改善肉鸭的饲料转化率（P〈0．01），提高经济效益；肉鸭的增重和饲料转化率，试验组间没有显著差异（P〉0．05）。     

高油脂日粮中添加外源性乳化剂对肉鸡饲料养分利用率的影响

选用48只体重一致的、健康的36日龄的爱拔益加(Arbor Acre)雄性肉鸡,随机分成6个处理,每个处理4个重复,研究等能和等蛋白情况下,在高油脂含量日粮中添加不同剂量(0、400、530、660、800g/t)的外源性乳化剂对肉鸡饲料营养物质表观和真实代谢率的影响。结果表明:高油脂饲料中添加不同水平的外源性乳化剂不同程度地提高了能量、粗脂肪和干物质的表观和真实代谢率以及表观和真实代谢能,并且随着乳化剂添加水平的提高而呈上升的趋势。其中800g/t乳化剂水平下,能量、粗脂肪的真实代谢率、真实代谢能都提高值最大,添加400g/t乳化剂处理组和对照组差异不显著。     

大豆磷脂对肉仔鸡脂肪沉积的影响

大豆磷脂是大豆油精制过程中的副产品———水化油脚及时加工制取的纯天然产品,因其具有乳化、分散、起泡、脱膜、降低黏度、保持水分、同蛋白质及淀粉结合等功能,在各行业中得到了广泛的应用。大豆磷脂在畜禽体内脂肪代谢、肌肉蛋白质沉积、神经系统发育和体内氧化发育等方面发挥着重要的作用。美国食品化学法典对商品磷脂作了如下定义:食品级磷脂来源于大豆与其他植物,他是由磷脂的丙酮不溶物组成的复杂混合物,其中主要是磷脂酰胆碱、磷脂酰乙醇胺及磷脂酰肌醇。大豆磷脂一般分为4类:浓缩磷脂,包括塑性磷脂与流质磷脂两种(脱色或非脱色型)…     

Effect of stachyose supplementation on growth performance, nutrient digestibility and caecal fermentation characteristics in broilers

1. The objective of this study was to evaluate whether the oligosaccharide stachyose enhances gastrointestinal tract health by fermentation and proliferation of desirable bacteria species and thus affects growth performance and nutrient digestibility in broilers. 2. A total of 432 1-d-old male Arbor Acres (AA) broilers were randomly allocated to one of 6 treatments, with 12 replicate pens per treatment and 6 birds per pen. Chicks were fed a maize-hamlet protein 300 (HP300) basal diet with 0, 4.0, 8.0, 12.0 or 16.0 g/kg stachyose. A sixth diet contained no HP300 but soybean meal (SBM) and provided 8.7 g/kg stachyose and 3.1 g/kg raffinose. The duration of the study was 42 d. 3. Stachyose contents above 12.0 g/kg depressed group body weights, average daily gain and feed/gain but not feed intake during the whole experimental period. Broiler growth decreased linearly and quadratically with increasing stachyose content. No differences were detected between diets supplemented with 12.0 g/kg stachyose and SBM. 4. Nutrient digestibility tended to decrease but not significantly with increasing stachyose. 5. Stachyose content had no significant positive effects on caecal pH, microflora population and the resulting short-chain fatty acid (SCFA) metabolites during the 42 d experiment, with only butyrate differing significantly in the initial period.     

Effect of feed supplementation with Satureja khuzistanica essential oil on performance and physiological parameters of broilers fed on wheat- or maize-based diets

1. The aim of this study was to evaluate various levels of Satureja khuzistanica essential oil (SKEO) on performance and physiological parameters of broilers fed on wheat- or maize-based diets.

2. Treatments consisted of two cereals (maize- or wheat-based diets) and three levels of SKEO)0, 250 and 500 mg/kg).

3. Feed intake (FI) and body weight gain (BWG) decreased in broilers fed on the wheat-based diets compared to the control diet. Dietary supplementation of 500 mg/kg SKEO increased FI and BWG. Dietary SKEO supplementation was effective in improving FI and BWG only in wheat-based diets and was effective in improving feed conversion ratio (FCR) in both diets.

4. Dietary supplementation of 500 mg/kg SKEO caused a significant decrease in plasma cholesterol and triglycerides. Also, plasma low-density lipoprotein concentration was decreased in broilers fed on 250 and 500 mg/kg of SKEO. Plasma cholesterol levels in birds fed on the wheat-based diets were lower than in those fed on maize-based diets.

5. Dietary supplementation of 500 mg/kg SKEO increased caecal population of Lactobacillus and reduced total bacterial and Escherichia coli count. Caecal population of Lactobacillus decreased in broilers fed on the wheat-based diets.

6. Digesta viscosity was increased in broilers fed on the wheat-based diets and decreased in broilers fed on 500 mg/kg SKEO compared to the control diet. Dietary SKEO supplementation was effective in reducing digesta viscosity values only in wheat-based diets.

7. Villus height of the duodenum and jejunum decreased in broilers fed on the wheat-based diets. Dietary supplementation of 500 mg/kg SKEO increased villus height and villus height-to-crypt depth ratios and decreased crypt depth of the duodenum compared to the control diet.

8. It can be concluded that dietary SKEO supplementation was effective in improving FI, BWG and FCR values in wheat-based diets.     

补饲青绿饲料对不同性别肉仔鸡屠宰品质的影响

试验旨在探讨饲喂全价基础日粮的基础上补饲青绿饲料对不同性别肉仔鸡屠宰品质的影响。选择1日龄健康AA肉鸡360只(公母各半),根据不同性别随机分成4组,每组3个重复,每重复30只。分别设为Ⅰ♂、Ⅱ♂、Ⅰ♀、Ⅱ♀组。Ⅰ♂和Ⅰ♀为对照组,饲喂全价基础日粮,Ⅱ♂和Ⅱ♀为试验组,全期补饲新鲜青绿饲料。分别于第14、28、42日龄(d)时取样进行屠宰品质分析。结果表明:①各试验日龄公鸡的体重高于母鸡(P<0.05或<0.01);42日龄时公鸡的屠宰率和半净膛率高于母鸡(P<0.05),腹脂率低于母鸡(P<0.05)。②补饲青绿饲料能显著提高肉仔鸡胸肌率(P<0.05)和降低腹脂率(P<0.05),42日龄时公鸡和母鸡的胸肌率分别提高了14.9%和16.4%,腹脂率分别降低了20.8%和22.2%。③补饲青绿饲料对肉仔鸡屠宰率、半净膛率、全净膛率和腿肌率无显著影响。④总体上补饲青绿饲料对母鸡屠宰品质的影响作用更大。     

Effect of fat supplementation on nitrogen utilisation of lambs and nitrogen emission from their manure

The effects of various fats on nitrogen digestion and metabolism of lambs and their manure were investigated in six isoenergetic diets (n = 6) with similar contents of absorbable protein. Treatments were either a control diet or diets containing 25 g/kg of additional ether extract from rumen-protected fat, coconut oil, rapeseed, sunflower seed or linseed. Fat supplementation resulted in trends for higher apparent nitrogen digestibilities (significant with coconut oil; P < 0.05, post hoc test) and body nitrogen retention (P < 0.1). Urinary nitrogen losses and their proportion of manure nitrogen did not differ significantly among groups as was also true for C / N ratio, dry matter, nitrogen and ammonia nitrogen contents of the manure. In the first week of manure storage, most fat supplements tended to decrease gaseous nitrogen emission as assessed by respiration chamber and mass balance measurements. These differences tended to be mitigated after 7 weeks of manure storage. Only the coconut-oil treatment still resulted in numerically lower nitrogen emissions. In conclusion, addition of fat source in the diet, in addition to increasing dietary energy and suppressing methanogenesis, can under certain circumstances decrease gaseous nitrogen emission from the manure.     

Influence of enzyme supplementation of maize-soyabean meal diets on carcase composition, whole-body nutrient accretion and total tract nutrient retention of broilers

1. Carcase composition, whole body nutrient accretion rates and total tract nutrient retention of broilers in response to supplemental phytase or carbohydrase and protease from 0 to 21 d of age were investigated. 2. A total of 480 broilers were allocated to 4 slaughter groups (SG) of 30, 150, 150 and 150 broilers. Thirty broilers, in 6 replicates of 5 birds, comprised the initial SG killed at d 0; 150 broilers were allocated to each of the d 7, 14 and 21 final SG. Broilers in the final SG were allocated to 5 treatments in a randomised complete block design; each treatment had 6 replicate cages of 5 broilers per replicate cage. 3. The diets were maize-wheat-soyabean based and the treatments were: (1) positive control which met NRC (1994) energy and nutrients requirements for broiler, (2) negative control (NC) deficient in metabolisable energy (ME) and P, (3) NC plus phytase added at 1000 FTU/kg, (4) NC plus cocktail of xylanase, amylase and protease (XAP), and (5) NC plus phytase and XAP. 4. Except for ash and Ca, the treatments had no effect on carcase composition. Phytase or XAP individually or combined had variable effects on body nutrient accretion rates at various age periods of the broilers compared with the NC diet. Phytase alone or combined with XAP consistently improved body accretion rates of DM, protein, fat, ash, Ca, and P. 5. Addition of phytase alone or combined with XAP to the NC diet improved total tract N and P retention compared with the NC diet. Cocktail of XAP alone or combined with phytase improved Ca retention. Combination of phytase and XAP improved metabolisable energy (ME) and dry matter retention. 6. Overall, the results showed that the exogenous enzymes used had greater effects on the rates of nutrient accumulation in the carcase rather than on the proportion of nutrients deposited in the carcase.     

Effects of inclusion of poultry by-product meal and enzyme-prebiotic supplementation in grower diets on performance and feed digestibility of broilers

1. Two experiments were conducted to determine the effects of level of inclusion of poultry by-product and enzyme-prebiotic supplementation on grower diet digestibility and the performance of broilers. 2. Six grower diets were formulated to provide a similar nutrient profile with the exception of using three graded levels of poultry by-product, namely 0, 25, 40 g/kg of the diet with and without supplementation of enzyme preparation at the rate of 1 kg per tonne of feed and prebiotic preparation at the rate of 2 kg per tonne of feed. The experimental diets were used from 3 to 6 weeks of age. 3. Body weights, feed intake and feed conversion efficiency were not affected by poultry by-product; however, enzyme-prebiotic had a significant positive effect on feed conversion efficiency at 0 to 6 weeks in experiment 1. 4. Crude protein digestibility was decreased by feeding the diet containing poultry by-product while ether extract digestibility was increased by poultry by-product at the rate of 25 g per kg of feed only. Dry matter retention, crude fibre digestibility and organic matter retention were not affected by poultry by-product. Dry matter and organic matter retentions, crude protein, ether extract and crude fibre digestibilities were not affected by enzyme-prebiotic. 5. Protein efficiency ratio (PER) values were increased by poultry by-product at the rate of 40 g per kg of feed and addition of enzyme-prebiotic.