高粱的加工、粒度和水分对饲料制粒和肉鸡生长性能的影响

本研究旨在评价不同水分和颗粒粒度的高粱制粒或膨化对不同原料粒度、肉鸡代谢能、氨基酸回肠消化率和肉鸡生长性能的影响。试验以720只雄性雏鸡为研究对象,随机分为6组,每组6个重复,每个重复20只。试验处理以2×2×2因子设计,即2种加工方式(制粒和膨化),2个调质水分(1.6%和0.8%),2个颗粒粉碎粒度(650和850μm)。结果显示:在添加1.6%水分的膨化日粮中,制粒制粒和颗粒耐久指数较高。850μm的粒径增加了饲料颗粒耐久指数。各处理组对肉鸡日增重和屠体性状均无显著影响(P>0.05)。在10~13 d饲喂颗粒饲料和添加1.6%水分的饲料的肉鸡表观代谢能和氮校正代谢能均较高(P<0.05),与添加膨化性饲料相比,高粱制粒饲料回肠赖氨酸和甘氨酸消化系数显著提高(P<0.05)。在评价饲料加湿效果时,饲料添加1.6%水分后赖氨酸、蛋氨酸、胱氨酸、甘氨酸、组氨酸、异亮氨酸和精氨酸回肠表观消化系数显著升高(P<0.05)。1.6%水分的膨化饲料较0.8%水分显著提高了21 d肉鸡采食量(P<0.05),在42 d时,0.8%水分的颗粒饲料显著提高了采食量(P<0.05)。结论:以650μm的粉碎粒度和1.6%的水分制备颗粒饲料在肉鸡生长后期可以提高回肠氨基酸消化率和表观代谢能,而膨化工艺提高了42 d肉鸡饲料颗粒制粒和饲料转化率。     

Utilization of potato peels and sugar beet pulp with and without enzyme supplementation in broiler chicken diets: effects on performance,serum biochemical indices and carcass traits

This study was conducted to investigate the effects of including potato peels (PP) and sugar beet pulp (SBP), as unconventional feeds, with and without enzyme in broiler diets from 1 to 42 days of age by observing the growth performance, blood parameters and carcass characteristics. A total of 150, 1‐day old, chicks were randomly assigned into five groups, each with 30 chicks. Birds in group 1 were fed on the control diet. Chicks in groups 2 and 3 were offered diets containing PP and SBP at the rate of 15% and 7.5%, respectively, while those in groups 4 and 5 were fed the same diets but with adding an enzyme mixture. Using the unconventional feeds in the diets was found to decrease the body weight (BW). However, the feed intake, weight gain and feed conversion did not differ from the control in PP at the grower period, but decreased in SBP throughout the experiment. Addition of enzyme greatly improved the BW in PP and SBP to a degree that it surpasses the control and also increased the feed intake and conversion. The total cholesterol and low‐density lipoprotein cholesterol serum levels were decreased in all tested groups. Carcass yield was not affected by treatments, but the carcass fat content was reduced using the unconventional feeds with or without enzyme. In conclusion, PP can be used at a rate of 15% in the grower diets of broilers. Furthermore, 15% PP or 7.5% SBP can be included in starter and grower diets, but with the addition of enzymes. This can help in solving the problem of current shortage and rising costs of conventional feeds.     

Phytase dose effects in practically formulated diets that vary in ingredient composition on feed manufacturing and broiler performance

Considering approaches to efficiently produce broiler chickens, an experiment was conducted to describe the manufacturing and feeding effects of a corn, soybean meal, and wheat based diet with varying levels of corn distillers dried grains with solubles (DDGS) and commercial phytase. Treatments were arranged in a 3 × 2 factorial randomized complete block design varying in phytase (zero, 1,000, and 6,000 FTU/kg) and DDGS inclusion (zero or 5%). Phytase inclusion decreased dietary non-phytate phosphorous (nPP) and total Calcium (Ca) in formulation by 0.12 and 0.1%, respectively. Diets were steam conditioned at 82°C for 10 s, extruded through a 4.7 × 38 mm pellet die, and fed as crumbles (starter and grower) or pellets (finisher). Ten replicate pens of straight-run Hubbard × Cobb 500 chicks consumed one of 6 dietary treatments for 38 days. Phytase improved feed conversion ratio (FCR) in the starter period (P = 0.05), but benefits were not apparent in the grower or finisher periods. Phytase and formulation main effects interacted to affect overall FCR (P = 0.05), demonstrating a 0.05 decrease in FCR when birds were fed a diet containing a super-dose of phytase and without DDGS relative to diets containing a super-dose of phytase and DDGS. The DDGS likely provided reduced nutrient availability relative to their nutrient values used for diet formulation or provided non-starch polysaccharides (NSP) at a level that decreased bird performance. Based on tibia ash measures, performance improvement associated with the super-dose of phytase was likely associated with reducing phytate phosphorus gastrointestinal irritation rather than meeting bird phosphorus requirement.     

活性酵母在肉鸡日粮中的应用效果初探

选择1日龄岭南黄肉雏鸡1000羽,随机分成5个处理组,每组设4个重复,每个重复50羽(公母各半)。各处理组肉鸡日粮分别添加活性酵母菌0×107(对照)、0.5×107、1×107、2×107、4×107CFU/g。结果显示,肉鸡日粮中添加活性酵母1×107CFU/g或2×107CFU/g可显著提高肉鸡肠道淀粉酶、脂肪酶和胃蛋白酶的活性(P<0.05)。活性酵母显示出提高肉鸡平均日增重、降低耗料增重比的作用,但均未达到显著水平(P>0.05)。盲肠内容物微生物检测结果提示,日粮中添加活性酵母有改善肉鸡肠道微生态环境的趋势。     

β-羟基-β-甲基丁酸对肉仔鸡生长性能和屠宰性能的影响

选择240只7日龄肉仔鸡按照体重相近原则随机分为5组,每组6个重复,每个重复8只,分别饲喂添加0%、0.01%、0.055%、0.1%、0.145% β-羟基-β-甲基丁酸(HMB)的试验日粮.采用三层笼养,试验期35 d.试验结果表明:(1)不同水平HMB对肉仔鸡生产性能的总体影响不显著.7～21日龄时,与对照组相比,0.145% HMB组内仔鸡料重比降低6.06%(P＞0.05);0.1%和O.145%HMB肥组肉仔鸡死亡率低于对照组水平.22～42日龄时,0.145%HMB组肉仔鸡采食量与对照组相比降低9.94%,各处理组体增重和料重比差异不显著(P＞0.05);7～42日龄时.0.145%HMB组肉仔鸡采食量与对照组相比降低9.03%(P＜0.05),各处理问体增重和料重比无显著差异,但0.145%HMB组肉鸡料重比最小.0.1%和0.145%HMB组肉仔鸡死亡率低于对照组和其他处理组.(2)肉仔鸡的屠宰性能包括屠宰率、半净膛、全净膛率、胸肌率、腿肌率和腹脂率在各处理问无显著差异(P＞0.05),0.145%HMB组肉仔鸡腿肌率较对照组提高3.74%(P＝0.075).可见,在7～42日龄内仔鸡日粮中添加适量的HMB可显著降低肉仔鸡采食量.而体增重和饲料效率无显著变化,并有促进肉仔鸡腿部肌肉生长发育的趋势.     

The effects of pelleting and glucanase supplementation in hulled barley based diets on feed manufacture,broiler performance,and digesta viscosity

Feeding broilers barley-based diets requires special consideration primarily due to effects on increased digesta viscosity and decreased nutrient digestion. Pelleting and glucanase supplementation are commonly performed prior to feeding broilers barley-based diets; however, the interaction of these practices is complex. The objective of this study was to establish a comprehensive evaluation of glucanase efficacy including: degree of processing, activity postpelleting, broiler performance, and digesta viscosity. Treatments were arranged in a 5 (diet formulation) × 2 (processing) factorial in a randomized complete block design with 8 replications/treatment. The 5 diet formulations consisted of positive control (PC), negative control (NC), glucanase A (GA) 125 or 1,000 β-Glu-U/kg feed, and glucanase B (GB) 1,000 β-Glu-U/kg feed. The PC and NC diets differed in metabolizable energy by 150 kcal/kg and enzymes were added to NC formulations. Diets were either fed as unprocessed mash or ground pellets. Diet formulation × processing did not interact for feed intake (FI), FCR, or total tract viscosity (P > 0.05); however, a trend was observed for ending bird weight, demonstrating that for ground pellets, GA 1,000 β-Glu-U/kg feed was improved relative to NC and similar to PC (P = 0.0903). Benefits associated with GB were not of similar magnitude, perhaps in part due to a 50% decrease in activity postpelleting. In addition, GA benefits were not suggested for unprocessed mash. The main effect processing was significant (P < 0.0001) demonstrating that broilers fed ground pellets resulted in greater pen ending bird weight, FI, and bird live weight gain (LWG) compared to birds fed unprocessed mash diets. Evaluations of glucanase should go beyond in vitro activity and include live bird performance using feed that has undergone pelleting.     

The influence of whole grain inclusion in pelleted broiler diets on proventricular dilatation and ascites mortality

1. Pelleted diets, incorporating whole or ground wheat or barley in the pellets, were fed to broiler chickens and proventricular dilatation, digesta characteristics and mortality were recorded. 2. The incidence of proventricular dilatation was reduced when whole grain was incorporated into pelleted diets at 200 g/kg. 3. Enzyme application did not influence proventricular dilatation. 4. Digesta contents of intestinal sections were greater and pH lower in anterior intestinal sections when birds had dilated proventriculi. 5. Consideration of overall ascites mortality suggests that the incidence of the condition may be curtailed by whole grain inclusion in pelleted diets. 6. Production efficiency may be enhanced with whole grain inclusion in pellets when feed processing costs and flock health responses are considered.     

Influence of inclusion level of barley in wheat-based diets and supplementation of carbohydrase on growth performance,nutrient utilisation and gut morphometry in broiler starters

ABSTRACT

1. The influence of barley inclusion level and supplementation of a multi-component non-starch polysaccharide degrading enzyme on performance and nutrient utilisation in broilers was investigated. Normal-starch hulled barley was evaluated with five levels of inclusion (0, 141, 283, 424 and 565 g/kg) in a wheat-based diet and two levels of enzyme supplementation (0 and 150 g/tonne of feed; a 5 × 2 factorial arrangement of 10 dietary treatments). All diets were equivalent in metabolisable energy and digestible amino acid contents. 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, weight gain (WG) increased up to 283 g/kg of barley and was reduced afterwards (P < 0.01). Increasing levels of barley resulted in greater (P < 0.001) gain per feed (G/F). Enzyme addition increased WG (P < 0.05) and G/F (P < 0.001) at each barley inclusion level.

3. Birds fed diets with 0 and 565 g/kg barley showed the lowest and highest (P < 0.001to 0.05) digestibility for all nutrients measured, respectively. Digestibility of all nutrients was improved by enzyme supplementation at each barley inclusion level (P < 0.05). The nitrogen-corrected apparent metabolisable energy improved with increasing inclusion of barley (P < 0.001) and supplemental enzyme (P < 0.01). Increasing inclusion of barley increased the relative weight of gizzard (P < 0.001) and reduced jejunal digesta viscosity (P < 0.001). Supplemental enzyme (P < 0.001) reduced digesta viscosity.

4. The optimum inclusion level of barley, with respect to growth performance, was 283 g/kg of diet. Increasing barley inclusion improved nutrient and energy utilisation, possibly through lowered digesta viscosity and better function of the gizzard. Feed efficiency and nutrient and energy utilisation can benefit from carbohydrase supplementation in barley-based diets, regardless of barley inclusion level.     

Effect of cereal type and Xylanase supplementation on nutrient retention and growth performance of broilers

An experiment was conducted to study the effect of cereal (corn, wheat, barley and sorghum) and supplemental enzyme (a mono-component xylanase) in a 4 × 2 factorial arrangement. A 2-phase feeding program (0 to 21 and 21 to 42 d) was used and 4 iso-caloric, iso-nitrogenous diets were formulated containing corn, wheat, barley, or sorghum as the sole cereal. Diets based on each cereal were fed without or with supplemental xylanase (16,000 BXU/kg) to 8 replicate pens of 10 chicks (5 male : 5 female, Cobb 500) each. Growth performance was recorded at 21 or 42 d posthatch. Excreta was quantitatively collected from 18 to 21 and 38 to 41 d for the measurement of the total tract retention of dry matter (DM), nitrogen (N) and neutral detergent fiber (NDF) and apparent metabolizable energy (AME). Ileal digestible energy (IDE) was measured at the end of the study (42 d posthatch) using titanium dioxide as an indigestible marker. For the overall 42 d period, birds fed barley-based diets had lower feed intake (P < 0.05), lower body weight (P < 0.05) and converted feed into gain less efficiently (P < 0.05) compared with the diets based on corn, wheat or sorghum. Xylanase supplementation improved weight gain in diets based on corn, wheat, and sorghum with the exception of barley-based diets (cereal × xylanase interaction, P < 0.05). Xylanase improved the overall feed conversion ratio (1.885 vs. 1.939; P < 0.05) with the effect being independent of the cereal type. The N retention of barley-based diets was lower (P < 0.05) compared with the other cereals, while xylanase improved N retention (P < 0.05) regardless of the cereal type. NDF digestibility differed (P < 0.05) across cereal (barley > wheat > corn > sorghum) and was improved (P < 0.05) by xylanase supplementation. A significant cereal × xylanase interaction (P < 0.05) was observed for energy measurements, where xylanase improved IDE of the corn-based diet, and AME of corn- and wheat-based diets. Results of the current study demonstrate potential of xylanase in improving nutrient retention and growth performance of broilers fed diets based on variety of cereal grains.