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。     

Effects of feeding cracked corn and concentrate protein pellets on broiler growth performance

Typically, in a vertically integrated poultry (broiler or turkey) operation, maintaining adequate feed manufacturing production proves to be a challenge. To evaluate an alternative management strategy, 2 studies were conducted to examine the effects of feeding broilers cracked corn and a concentrated pellet on broiler growth performance from 0 to 41 d of age. Cracked corn (0, 25, 50, 75, or 100%) was used to replace the corn fraction in the diet for all 3 stages of growth. Cracked corn and concentrate pellets were blended together to be isonitrogenous and isocaloric among all treatments, so only feed form would differ. Experiment 1 diets included a control (0% cracked corn) and experimental diets (25, 50, 75, or 100%) in which cracked corn directly replaced the ground corn fraction. Overall (0 to 41 d), a linear decrease (P < 0.001) for ADG and ADFI and a linear increase (P < 0.003) for FCR was observed as cracked corn levels increased. In experiment 2, a “step-up” feeding program of cracked corn was evaluated with dietary treatments including the following: 1) control (0% cracked corn throughout feeding), 2) 0% cracked corn (0 to 17 d) and 25% (18 to 41 d), 3) 0% cracked corn (0 to 17 d) and 50% (18 to 41 d), 4) 25% cracked corn (0 to 41 d), and 5) 50% cracked corn (0 to 41 d). Overall (0 to 41 d), ADG for treatment 1, 2, and 4 was greater than 3 and 5 (P < 0.05). Feed conversion ratio was superior for treatments 2 and 4 (P < 0.05) in comparison with treatments 3 and 5. Up to 25% of the dietary corn can be fed to the broiler as cracked corn from 0 to 41 d without a negative response on growth performance.     

早期数量限饲对肉用仔鸡生产性能、胴体品质的影响

试验研究了早期数量限饲对肉用仔鸡生产性能、胴体品质的影响。以320只1日龄AA+肉用仔鸡为试验动物。设4个处理组,每个处理组4个重复,每个重复20只肉仔鸡。对照组根据AA+商品代肉鸡营养标准配制。各处理肉用仔鸡1～7日龄均为自由采食,8～14日龄对照组、限饲90%组、限饲80%组和限饲70%组分别饲喂自由采食量的100%、90%、80%和70%,15日龄恢复自由采食,以后按常规饲养管理。每周末,以重复为单位全部称重。分别于42、49日龄,每个重复随机抽取4只肉用仔鸡禁食12h、称重、屠宰、测定屠体品质。试验结果表明:在第2周,限饲各组肉仔鸡的体重和日增重分别显著低于对照组(P0.05);在第3周,限饲90%组完成补偿生长,体重与对照组差异不显著(P0.05);在第4周,限饲80%和70%组完成补偿生长,体重与对照组差异不显著(P0.05);5、6、7周及2～6、2～7周各组在体重、日增重、日采食量和饲料转化率等都无显著差异(P0.05)。早期数量限饲对肉仔鸡胴体特性没有显著影响(P0.05),限饲70%～80%,具有改善饲料转化效率、胸肌率、腹脂率的作用。     

The effects of strain and incremental improvements in feed form on d 28 to 42 male broiler performance

Feeding high-quality pellets to modern commercial broilers may maximize genetic potential; however, this typically requires an increased cost to produce feed. Therefore, it is important to determine if incremental improvements in feed form (FF) can increase performance of modern broiler strains. The current study was conducted to investigate the effects of feeding modest improvements in feed form (50, 60, 70, or 80% intact pellets; IP) to 2 commercial broiler strains (fast-growing or high-yield) on d 28 to 42 growth performance and processing variables. A common diet was manufactured to contain 80% IP, of which a portion was ground to create a total of 4 FF treatments varying in IP to ground pellet ratios: 50:50; 60:40; 70:30; and 80:20. Fast-growing (FG) birds demonstrated improvements in body weight (BW), BW gain (BWG), and feed conversion ratio (FCR) when compared to high-yield (HY) birds. For the main effect of FF, feeding 80 vs. 50% IP reduced d 28 to 42 FCR. Also, feeding birds 80% IP vs. all other FF treatments improved d 28 to 42 BWG and d 42 BW. A Strain × FF interaction established that FG broilers fed 50, 60, and 70% IP diets had higher d 43 total breast yield than HY birds fed the same FF treatments; however, both strains demonstrated similar total breast yield when 80% IP were fed, which suggests that FG broilers are less sensitive and HY broilers are more sensitive to increasing FF. These data suggest a distinct benefit for feeding improved FF from d 28 to 42 to modern broilers.     

Effects of egg weight on the egg quality,chick quality,and broiler performance at the later stages of production (week 60) in broiler breeders

The objective of the present study was to determine the effect of broiler breeder egg weight on egg quality, chick quality, and broiler performance using Hubbard Classic broiler breeder flock. Hatching eggs from a commercial broiler breeder flock (Hubbard classic strain) were obtained at the age of 60 wk and divided into 3 egg-weight categories, namely small, medium, and large. For this purpose, 930 eggs having weights 63.09 ± 0.21, 68.85 ± 0.23, and 74.81 ± 0.11g were divided into 3 egg categories labeled small, medium, and large respectively. We further divided these eggs into 2 categories, eggs for quality parameters and eggs for incubation and posthatch performance parameters. Eggs from the small egg category had greater proportion of the shell weight and more shell strength. Egg weight did not significantly affect the albumen and yolk weight percentage. Egg weight affected the shape index and specific gravity for which lower values were observed for large eggs. Egg weight positively affected the chick weight, chick yield, and chick length (P < 0.05) of both male and female chicks. Results of the body weight gain showed that effect of egg weight on the posthatch performance of chick diminishes with the age of broilers. Egg weight significantly affected the body weight gain of male and female chicks up to 3 wk of age. Egg weights did not significantly affect the feed intake and mortality of broiler. Different egg-weight categories significantly affected the feed conversion ratio of female chicks at wk 2 and 3 of age and did not affect the feed conversion of male and female chicks at the end of wk 5. In conclusion, egg weight positively affected the chick characteristics (e.g., chick weight, chick length) and did not affect the final live body weight, feed conversion ratio, feed intake, and mortality in broilers.     

Effects of the addition of roller mill ground corn to pelleted feed during a fifty-six-day production period on growth performance and processing yields of broiler chickens

Poor pelleting production rates can raise the milling cost and increase the frequency of feed outages for broiler integrated operations. The number of broilers marketed to heavy BW has been increasing, and meeting feed delivery schedules can be problematic with “big bird” complexes. Adding rolled corn post pellet is a management strategy to increase feed production rate while concurrently decreasing energy use of the grinding and pelleting processes. This study evaluated the addition of screened rolled corn to pelleted feed on live performance and meat yield of broiler chickens during a 56-d grow-out. Four dietary treatments were provided: A) a control, no added corn post pellet from 18 to 56 d of age; B) addition of 25% of the formulated corn post pellet from 18 to 56 d of age; C) addition of 10, 20, and 30% of the formulated corn post pellet from 18 to 35, 36 to 46, and 47 to 56 d of age, respectively; and D) addition of 20, 30, and 40% of the formulated corn post pellet from 18 to 35, 36 to 46, and 47 to 56 d of age, respectively. Final BW, cumulative feed conversion, 38-d BW uniformity, and 57-d breast meat weight and yield were similar among the dietary treatments. These results indicate screened rolled corn can be added post pellet without adversely affecting broiler performance and meat yield.