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1.
Providing broilers diets formulated to a high amino acid density early in life improves subsequent growth performance and meat yield. Diets formulated to high amino acid concentrations beyond 5 wk of age may increase breast meat yield but may not be economically justified. This study examined growth, meat yield, and economic responses of broilers provided diets varying in amino acid density from 36 to 59 d of age. Birds were given a 4-phase feeding program: starter (1 to 17 d), grower (18 to 35 d), withdrawal-1 (WD1; 36 to 47 d), and withdrawal-2 (WD2; 48 to 59 d of age). All birds were fed a common, high amino acid density diet to 35 d of age (HH). Broilers were provided diets characterized as being high (H), moderate (M), or low (L) in amino acid density for the WD1 and WD2 periods. Dietary treatments were HHHH, HHHM, HHHL, HHMM, HHML, and HHLL from d 1 to 59, with H, M, and L representing the diets fed during each of the 4 periods (starter, grower, WD1 and WD2).Cumulative feed conversion was improved when the HHHH feeding regimen was fed, whereas other final live performance measurements were not affected. Decreasing amino acid density (HHLL and HHHL) limited yields of breast fillets, tenders, and total white meat when compared with the HHHH regimen. As amino acid density decreased from HHHH to HHHM, HHMM, and HHML, carcass yield and breast meat yield were not affected. In general, providing the HHHH feeding regimen increased economic gross feeding margin compared with the other dietary treatments.  相似文献   

2.
Two experiments (EXP) were conducted to evaluate the interactive effects of dietary AME and amino acid (AA) density (total basis) on broiler chickens from 42 to 56 d of age. In EXP 1, diets were formulated to contain low AME (3,140 kcal/kg) and moderate AME (3,240 kcal/kg) in combination with moderate AA (16.2% CP, 0.88% Lys, and 0.75% TSAA) and high AA (18.0% CP, 0.98% Lys, and 0.83% TSAA) and fed to male broilers. Dietary treatments in EXP 2 were diets formulated to contain moderate AME (3,220 kcal/kg) and high AME (3,310 kcal/kg) combined with moderate and high AA concentrations used in EXP 1 and fed to male and female broilers. In general, dietary AME and AA did not interact to influence growth and meat yield responses. Broilers provided the low AME diet in EXP 1 consumed more feed and had poorer feed conversion but had higher total breast meat yield than birds fed the moderate AME diet. In EXP 2, broilers fed the high AME diet from 42 to 56 d had increased BW gain, decreased feed consumption, and improved feed conversion. Feeding the high AA diets in both EXP decreased feed consumption, improved feed conversion, and increased total breast meat yield. Nutritionists establishing nutritional programs for heavy broilers late in development from 2.5 to 3.6 kg may need to consider increasing AA density to optimize breast meat yield. Increasing the AME content of the diet improves feed conversion but not breast meat yield.  相似文献   

3.
The effects of dietary amino acid (AA) density and AME on the growth and meat yield of summer-reared Cobb × Cobb 700 (CCB-700) broilers were evaluated. In addition, the responses of CCB-700 and Cobb × Cobb 500 (CCB-500) broilers to dietary AME levels (with low AA) were compared. All chicks were fed through a starter, grower, finisher, and withdrawal phase program. Grow-out performance, carcass traits, meat yield, and feed cost efficiency were evaluated using 2 separate 2-way ANOVA based on 2 separate 2 × 2 factorial arrangements of treatments. Each group includes 14 replicate pens with 14 chicks/replicate. Mortality was not affected by treatment; however, as compared with birds fed other diets, feeding CCB-700 broilers a low-AME and high-AA density diet decreased feed intake and BW on d 35, 42, and 54, and decreased carcass, breast, wing, front half, and back half weights on d 55. The CCB-500 broilers consumed more feed and gained more weight as compared with CCB-700 broilers at 14, 28, and 35 d of age. However, at 55 d of age, breast weight and wing yield were observed to be higher in the CCB-700 than in the CCB-500 broilers. However, the back half (drumstick and thigh) weights were lower in the CCB-700 than in the CCB-500 broilers. In conclusion, without affecting feed costs, broiler performance and carcass yield were affected by diet in both strains. More specifically, a higher AME diet and lower AA density increased the yield of all cut-up parts, except for legs, in summer-reared CCB-700 chicks.  相似文献   

4.
This study examined growth responses and meat yield of broilers provided a 3- or 4-phase feeding schedule formulated to moderate or high nutrient density. Four dietary treatments were implemented consisting of high or moderate nutrient density diets that were provided for the duration of 3 phases (1 to 17, 18 to 35, and 36 to 56 d) or 4 phases (1 to 17, 18 to 35, 36 to 46, and 47 to 56 d).Provision of a 3-phase schedule did not alter growth performance, meat yield, or diet cost per final BW. Broilers receiving high nutrient diets had improved growth rate and feed conversion from 1 to 35 d. In the 3-phase schedule, birds given the high nutrient density diets had advantages in BW gain and pectoralis minor breast weight. Market changes in meat prices impact differences in gross feeding margins between diets formulated to high or moderate nutrient density more than variation in diet cost.  相似文献   

5.
Nutritional modulation of live performance and meat yield must be continuously tested as broiler strains become more efficient every year. This study evaluates both copper- and lysine-derived amino acid balance. In experiment 1, amino acid balance (high, moderate, and low) and copper (5 and 200 ppm) were investigated in a factorial array of treatments (6 treatments with 8 replications; 1,536 Cobb 500 male broilers across 48 floor pens from 1–40 d of age; 32 birds per pen). In experiment 2, amino acid density (high and low) was assessed in 2 broiler strains (a multipurpose and a high-yield strain) obtained from the field in a factorial array of treatments (4 treatments with 21 replications; 1,344 multipurpose and 1,344 high-yield broilers across 84 floor pens from 1–42 d of age; 32 birds per pen). Amino acid density treatments were created by altering digestible lysine and other essentials amino acids at a fixed ratio. Copper and amino acid density did not interact, but supplementing broilers with 200 ppm of copper in the form of tribasic copper chloride improved growth rate. Lysine-derived amino acid density improved performance and yields, but should be assessed as strains are improved for efficiency to ensure digestible lysine adequacy in the nutrient formulation matrix. Although both copper and lysine influence growth rate, interactive effects were not assessed in this study.  相似文献   

6.
1. Herbs, thyme essential oil (EO) and condensed tannin (CT) extracts were compared for their effects, as dietary supplements, on broiler growth performance, nutrient digestibility and volatile fatty acid (VFA) profiles in the gut. Cooked meat from the birds fed on diets with 4 herbs and an EO extract was compared by a taste panel against those fed on the control treatment, for organoleptic properties in the meat. 2. Female broiler chicks were fed on wheat-soybean meal diets from 0-42 d of age. These chicks were given either the basal diet (control), or the basal diet with one of rosemary, garlic or yarrow herbs, mimosa, cranberry or grapeseed CT's, or thyme EO supplements (8 treatments in total). Body weight (BW) and feed consumption (FC) were measured. 3. The garlic supplement tended to improve growth rate over the first 7 d, while mimosa CT and thyme EO supplements reduced weight gains. The mimosa supplement in diets significantly reduced FC to d 21. Meanwhile, the addition of a cranberry supplement reduced the digestibility of DM, OM and N, compared with the controls. Dietary thyme EO, yarrow, rosemary and garlic supplements modified caecal isovaleric and isobutyric acid proportions (presented as 'Other VFA'; p < 0.05). Dietary herb significantly affected the intensity of meat flavour, and the potential of observing both garlic and abnormal flavours. There were large differences between the consumption of red and white meat samples, while meat temperature affected several flavour attributes. 4. Broiler performance and digestibility for birds given dietary garlic and grapeseed CT supplements were similar to the controls, and these supplements appear suitable for dietary inclusion. Careful choices are necessary when selecting dietary plant extract supplements for broilers, but beneficial effects can be observed.  相似文献   

7.
Precocious puberty (<300 d of age) can be successfully induced in a majority of heifers with early weaning and continuous feeding of a high-concentrate diet. The objective of this experiment was to determine the relative effects of timing of feeding a high-concentrate diet on age at puberty in early-weaned heifers. Sixty crossbred Angus and Simmental heifer calves were weaned at 112 +/- 2 d of age and 155 +/- 3 kg of BW and were fed a receiving diet for 2 wk. Heifers were blocked by age and BW, and assigned randomly to receive a high-concentrate (60% corn; H) or control (30% corn; C) diet during phase 1 (mean age 126 to 196 d) and H or C during phase 2 (mean age 196 to 402 d), resulting in 4 treatments (HH, n = 15; HC, n = 15; CH, n = 15; and CC, n = 15). Blood samples were collected weekly beginning at a mean age of 175 d and assayed for progesterone concentration to determine age at puberty. After 56 d on the experimental diets, BW of heifers fed the H diet during phase 1 were greater (P < 0.05) than those of heifers fed the C diet (mean age of 182 d; treatment x mean age, P < 0.01). After 70 d on the new diets (mean age of 266 d), heifers fed the H diet during phase 2 reached heavier BW (P < 0.05) than heifers fed the C diet, when compared within phase 1 diet groups (HH > HC; CH > CC). Body weights in HC and CH treatments differed from a mean age of 169 through 238 d, after which BW did not differ between these treatments. The ADG over the entire experimental period was greatest for the HH treatment (1.2 +/- 0.04 kg/d; P < 0.05), followed by the HC and CH treatments (1.0 +/- 0.03 and 1.0 +/- 0.02 kg/d, respectively), which were not different, and the CC treatment gained the least (0.7 +/- 0.04 kg/d; P < 0.05). Precocious puberty occurred in 67, 47, 47, and 20% of heifers in the HH, HC, CH, and CC treatments, respectively (HH > CC; P < 0.05). Mean age at puberty for the HH and HC treatments (271 +/- 17 and 283 +/- 17 d of age, respectively) was earlier (P < 0.05) than for the CC treatment (331 +/- 11 d of age). Age at puberty in the CH treatment (304 +/- 13 d of age) was intermediate to and not different from the other treatments. Heifers fed the H diet during phase 1 attained puberty earlier (P < 0.05) than heifers fed the C diet during phase 1. In conclusion, increasing dietary energy intake in early-weaned heifers, through feeding a high-concentrate diet from 126 to 196 d of age, decreased age at puberty regardless of the diet fed after 196 d of age.  相似文献   

8.
1. Two experiments were conducted to determine the effects of dietary nucleotide supplementation on broiler performance, and physical and morphological development of the gastrointestinal tract.

2. Experiment 1: A total of 180 one-d-old male chicks were placed in battery brooders in 3?×?6 replicate pens containing 10 chicks each. Chicks were randomly assigned to one of the three dietary treatments; a maize-soyabean meal based diet supplemented with 0, 0·25, and 0·50% Torula yeast RNA (as a source of nucleotides) from 0 to 16?d of age.

3. Experiment 2: A total of 1344 one-d-old male chicks were placed in floor pens and reared on recycled wood shavings (two flocks) under a high stocking density (0·068?m2/bird). Chicks were randomly assigned to one of the 4 dietary treatments (0, 0·25% Torula yeast RNA, 2% and 6% Nupro®) for the starter period (0 to 14?d of age) with 6 replicate pens containing 56 chicks each. All the birds were fed on the same common grower diet with no supplementation of nucleotides from 15 to 32?d of age.

4. Experiment 1: Supplementing the diets with up to 0·50% Torula yeast RNA did not affect broiler performance, or relative intestinal tract weight and length of broilers at any periods measured.

5. Experiment 2: From 0 to 14?d of age, broilers fed on the diets supplemented with 0·25% Torula yeast RNA and 2 and 6% Nupro® were significantly heavier and had improved feed conversion (feed:gain) ratios as compared with the birds fed on the control diet. Supplementing the starter diet only with 2% Nupro® supplementation significantly improved body weight (BW) gain as compared with the control diet over the entire experiment (0 to 32?d of age). Broilers fed on the diets supplemented with 2 and 6% Nupro® from 0 to 14?d of age had better feed conversion (feed:gain) ratios over the entire experiment (0 to 32?d of age) as compared with the birds fed on the control diet, even though the birds were only fed on the diets supplemented with Nupro® from 0 to 14?d of age. The broilers fed on the diets supplemented with 0·25% Torula yeast RNA and 2% Nupro® had higher villus height and an improved villus height-to-crypt depth ratio as compared with birds fed on the control or 6% Nupro® diet at 14?d of age.

6. It is generally assumed that nucleotides are not an essential nutrient; thus there is no need to supplement the diets of broilers reared under normal conditions. However, dietary nucleotide supplementation may be important to maintain maximum growth performance when birds are exposed to stress conditions, such as high stocking density combined with dirty litter.  相似文献   

9.
This study examined hatchery feeding of starter diets differing in amino acid density and moisture on live performance measurements up to 37 d and processing measurements at 38 d. Eggs from a Cobb × Cobb 500 slow-feathering cross broiler strain were set in a common incubator and hatched. Chicks were feather-sexed, placed in 36 chick trays (25 chicks of each sex), and weighed by tray. One of 4 dietary treatments was administered (454 g/tray) in crumble form: 1) no feed; 2) feed containing 1.24% digestible Lys, 0.84% digestible TSAA, 0.80% digestible Thr, 23.2% CP, and 3,080 kcal/kg of ME; 3) feed containing 1.45% digestible Lys, 0.94% digestible TSAA, 0.84% digestible Thr, 26.0% CP, and 3,080 kcal/kg of ME; and 4) treatment 3 plus 100 mL of potable water added to the crumbles 5 min before administration in the trays. Chicks received feed treatments in trays in the hatchery, during transportation to the research facility, and in the research facility until placement (5 h of total tray feeding). Body weight gain at d 7 was increased in birds fed the high density diet alone or in combination with water as compared with birds that were fasted. Subsequent live performance, processing, and small intestine weights, however, did not differ among treatments. Lack of 37-d improvements (average 4.6-lb birds) to early feed allocation may be a result of diet composition, duration of diet allocation, and the genetic strain of bird used, because much literature has pointed to the importance of posthatch nutrition of broilers.  相似文献   

10.
An experiment was conducted to evaluate the effects of diets containing low-, moderate-, or high-oil dried distillers dried grains with solubles (DDGS) included at conventional- or increased-inclusion rates fed to 1,500 Ross × Ross 708 male broilers that were assigned to 60 floor pens from 1 to 49 d of age. Three sources of DDGS had ether extract composition of 6.06, 8.80, or 11.59%, on dry matter (DM) basis, representing low-oil, moderate-oil, or high-oil DDGS, respectively. Diets were formulated to contain corn, soybean meal, animal protein meal as the primary ingredients, and 1 of the 3 DDGS sources at either 5, 7, 9, or 11% (conventional-inclusion rate) and 8, 10, 12, or 14% (increased-inclusion rate) in the starter (1 to 14 d), grower (15 to 24 d), finisher 1 (25 to 34 d), and finisher 2 (35 to 49 d) periods, respectively. Apparent MEn (low-oil:1,975, moderate-oil: 2,644, and high-oil: 3,137 kcal/kg) and digestible amino acid (AA) values of the 3 DDGS sources were determined from previous research. No differences were detected for cumulative BW gain and feed conversion 1 to 49 d of age or meat yields at 50 d of age. Feeding broilers diets containing the low-oil DDGS source increased feed cost per BW gain and breast meat weight of $0.025/kg and $0.004/kg compared with birds fed diets containing high-oil DDGS or moderate-oil and high-oil DDGS sources, respectively. These data indicated that DDGS source and inclusion rate did not affect cumulative growth and carcass characteristics of broilers from 1 to 50 d of age but demonstrate differences in feed cost/BW gain and feed cost/breast meat weight.  相似文献   

11.
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.  相似文献   

12.
Prior research indicated that foot ash determinations were as robust as tibia bone ash determinations in reflecting the degree of bone mineralization in chicks at 14 d of age. In the current research, the relative effectiveness of the 2 procedures was evaluated in 21- and 42-day-old broilers while also evaluating a new dietary phytase supplement. In experiment 1, broilers were fed until 21 d of age a negative control diet with 0.24% available phosphorus, a positive control diet with 0.48% available phosphorus, or the negative control diet supplemented with 300, 500, 1,000, or 2,500 phytase units/kg diet. In experiment 2, broilers were fed until 42 d of age negative control diets having 0.275, 0.250, and 0.225 percent available dietary phosphorus in the starter, grower, and finisher periods, respectively, positive control diets having 0.475, 0.450, and 0.425 percent available dietary phosphorus in the starter, grower, and finisher periods, respectively, or the negative control diets supplemented with 500, 1,000, or 2,500 phytase units/kg diet. At 21 and 42 d of age, broilers fed diets supplemented with the 2 highest doses of phytase had foot and tibia ash values equal to those fed the positive control diet and higher than those fed the negative control diet. At 42 d of age, feed conversion and total breast meat yield values for the broilers fed the highest dose of phytase were superior to the values of the birds fed the positive control diet or the diet containing the lowest dose of phytase. The results indicate that adding levels of this new dietary phytase beyond what is necessary for normal bone mineralization enhances feed conversion and that dried foot and tibia bone ash determinations are both reliable in detecting differences in bone mineralization in 21- and 42-day-old broilers.  相似文献   

13.
1. Two growth trials were performed to measure the effects of dietary methionine and cystine (SAA) on growth rate, food conversion efficiency and breast meat deposition in male broilers.

2. In experiment 1, broilers were grown on 6 experimental diets covering a range from 6.9 to 9.6 g SAA/kg. The diets were fed from 15 to 33 d of age. Similarly, in experiment 2, 6 diets containing 6.0 to 8.5 g SAA/kg were fed to finishing broilers 33 to 43 d of age. In each experiment 60 birds per treatment were processed, and carcase yield and breast meat percentage were determined.

3. Significant responses in weight gain, efficiency of food conversion and breast meat percentage were detected, which could be described well by exponential regression curves. Dietary SAA requirements to obtain maximum efficiency of food utilisation and maximum breast meat deposition were estimated to be about 9.0 g/kg from 15 to 33 d of age, and about 8.0 g/kg from 33 to 43 d of age.

4. Economic aspects were considered to calculate optimum SAA specifications from the results. In both trials, the dietary optimum of SAA was found to be higher for birds to be further processed than for birds to be marketed as whole carcases.  相似文献   


14.
During winter production, the optimum temperature set points for heavy broilers (>3.4 kg) approaching market weight are subject to debate in commercial practice. Apparent ME needed to optimize nutrient utilization may be influenced by ambient temperature. This experiment examined potential interactive effects of AME × ambient temperature from 36 to 60 d of age. A 4 × 2 factorial arrangement of treatments was used. Dietary treatments were diets formulated to 3,175, 3,220, 3,265, and 3,310 kcal of AME/kg. Two temperature regimens were provided consisting of variable temperature regimen (VTR) or constant temperature regimen (CTR) set points. The VRT was 21.1°C from 36 to 38 d of age, 20.2°C from 39 to 42 d of age, 18.9°C from 43 to 46 d of age, 17.8°C from 47 to 50 d of age, 15.6°C from 51 to 54 d of age, and 12.8°C from 55 to 60 d of age. The CTR was 21.1°C from 36 to 60 d of age. Significant AME × temperature interactions were observed for cumulative BW, BW gain, feed consumption, feed conversion, and mortality. In the CTR, increasing AME led to increased BW gain but not in the VTR. As dietary AME increased, the improvement in feed conversion was more pronounced in the CTR than the VTR. With the VTR, decreasing AME increased feed consumption. The experimental treatments did not influence abdominal fat percentage or total breast meat yield. These data provide evidence that broilers exposed to CTR respond to increased AME.  相似文献   

15.
为研究不同锰源与锰水平对肉仔鸡的生产性能与组织矿物元素沉积的影响,试验采用2×5完全随机试验设计,在玉米—豆粕型基础日粮(锰含量为37.66mg/kg)中添加0、45、90、130、180mg/kg(5个锰添加水平)的复合氨基酸锰和硫酸锰(2种锰源),构成10个日粮处理组,将540只1日龄健康艾维茵肉仔鸡随机分为10个处理组,开展肉仔鸡饲养试验(共42d)。于35日龄时测定其生产性能指标,计算料肉比;于42日龄时测定其胫骨、肝脏、肾脏组织中铜、铁、锌浓度以及胫骨灰分、钙及磷含量。结果表明,在上述日粮中,锰添加量在45~130mg/kg时,无论是添加复合氨基酸锰组还是添加硫酸锰组35日龄肉仔鸡体重和采食量较未添加组差异显著(P≤0.05),经分析,锰水平对其平均体重及采食量有极显著影响(P<0.01);不同锰源的35日龄肉仔鸡体重、采食量、料肉比差异不显著(P >0.05)。42日龄肉仔鸡胫骨、肝脏、肾脏组织中铜、锌、铁含量及胫骨灰分、钙磷含量未受锰源和锰水平及两者互作的显著影响(P >0.05)。由以上结果可以得出,锰水平对肉仔鸡生长性能有极显著影响(P<0.01);锰源对肉仔鸡生产性能无显著影响(P >0.05);锰源和锰水平及两者互作对肉仔鸡组织矿物元素沉积无显著影响(P >0.05)。  相似文献   

16.
1. Three experiments of 39 d were simultaneously conducted to assess the efficacy of three carbohydrase combinations on performance, apparent nutrient digestibility, intestinal morphology and digestive organ relative weights of chickens fed on a wheat-based diet. 2. Experiment 1 was performed under laboratory conditions, with the birds housed in cages. In experiment 2, the birds were placed in floor pens built in a commercial farm, and raised with their contemporaries at the farm. In experiment 3, broilers were reared under industrial management circumstances in commercial farms. A two-phase feeding programme was used: starter from 1 to 21 d of age and finisher from 22 to 39 d. The basal diet without supplementation (BD) and three enzyme preparations (BDF, BDP and BDR) were evaluated. 3. No differences in growth traits were observed among treatments in experiments 1 and 2. 4. When overall growing period was evaluated, all enzyme combinations improved apparent DM ileal digestibility of feed in the three experiments, but significant differences were only found in experiments 2 and 3. For this same period, an increase in apparent CP ileal digestibility of broiler chickens fed supplemented diets against the control group was found in experiment 3. Moreover, a significant greater apparent ileal fat digestibility in the enzyme treatments compared with the control group was shown when broilers were raised under industrial conditions (experiment 3). 5. Enzyme combinations had no effect on villus heights and crypt depths of broilers in experiment 1, whereas, in experiment 2, a greater villus height was found in BDF and BDP treatments than in control birds. 6. There were no differences in digestive organ relative weights among dietary treatments except for pancreas in experiment 1.  相似文献   

17.
The effect of duration of feeding (continuous or discontinued after d 14) and form (granular vs. powder) of spray-dried plasma (SDP) on performance and mortality of broilers using used litter was evaluated with 240 Ross × Ross 308 male broilers (6 broilers per pen, 8 pens per treatment). Dietary treatments were control (no SDP) or SDP as powder or granular included in the pellet and fed continuously (d 0 to 35) or discontinued after d 14. During the experiment, broilers developed necrotic enteritis, and tissue cultures were positive for Escherichia coli and Salmonella, resulting in 50% mortality on control broilers. Addition of SDP to the feed improved (P < 0.05) average daily gain, feed intake, and feed efficiency for each period of the study (d 0 to 14, 15 to 28, 29 to 35, and 0 to 35). Continuous feeding of SDP improved (P < 0.05) average daily gain, feed intake, and feed efficiency from d 15 to 35 compared with broilers fed SDP to d 14. Liveability was improved (P < 0.05) in broilers consuming SDP either for 14 d or continuously throughout the experiment compared with control broilers. Spray-dried granular plasma was more effective than spray-dried powder plasma from d 0 to 14. The results of this experiment confirmed that SDP improved broiler growth rate, feed intake, feed efficiency, and minimized enteric challenge associated with necrotic enteritis with maximal protection afforded by continuous feeding. The response to SDP was independent of age of the broiler.  相似文献   

18.
本试验旨在研究在2种能量水平饲粮中添加大豆卵磷脂乳化剂对肉鸡生长性能、养分利用率和血清生化指标的影响。试验采用2×2因子完全随机区组试验设计,将960只1日龄科宝500白羽肉公鸡随机分为4组,每组6个重复,每个重复40只鸡。各组试验鸡分别饲喂2个能量水平和2个乳化剂添加水平组成的试验饲粮,其中代谢能分别为12.13和11.92 MJ/kg(1～21日龄)、12.96和12.65 MJ/kg(22～49日龄),乳化剂添加水平分别为0和265 mg/kg(1～21日龄)、0和400 mg/kg(22～49日龄)。试验测定肉鸡生长性能,能量、干物质、粗蛋白质和粗脂肪表观利用率,以及血糖、血脂和胆汁酸含量。结果表明:肉鸡采食正常能量饲粮前期(1～21日龄)平均日增重极显著高于低能量饲粮(P<0.01),肉鸡全期(1～49日龄)采食添加乳化剂的低能量饲粮料重比能达到正常能量饲粮水平;饲粮添加乳化剂有提高平均日增重和饲粮粗脂肪和能量表观利用率的趋势,可促进胆汁分泌,能显著降低前期及全期料重比(P<0.05)。结果显示,降低饲粮能量显著降低1～21日龄肉鸡平均日增重,提高1～21日龄和1～49日龄料重比;饲粮添加乳化剂能够改善饲料利用率,特别是在1～21日龄肉鸡低能量饲粮中效果更明显。  相似文献   

19.
本试验旨在研究饲粮添加壳寡糖(COS)对肉鸡肉品质、抗氧化性能、小肠黏膜组织结构及肠道菌群的影响。选用300只1日龄健康的爱拔益加(AA)雄性肉鸡,随机分为5组,每组6个重复,每个重复10只鸡。空白对照组饲喂不含抗生素的基础饲粮,正对照组饲喂添加100 mg/kg金霉素的基础饲粮,试验组分别饲喂添加50、100和150 mg/kg COS的基础饲粮。试验期42 d。结果表明,与空白对照组相比:1)饲粮添加100 mg/kg COS显著提高了胸肌和腿肌的红度(a*)值(P0.05)。2)饲粮添加50和100 mg/kg COS显著提高了1~21日龄血清总超氧化物歧化酶(T-SOD)活性(P0.05),饲粮添加100 mg/kg COS显著提高了22~42日龄血清总抗氧化能力(T-AOC)和T-SOD、谷胱甘肽过氧化物酶(GSH-Px)活性(P0.05),饲粮添加50 mg/kg COS显著提高了22~42日龄血清T-SOD和GSH-Px活性(P0.05)。3)饲粮添加100 mg/kg COS显著提高了1~21日龄和22~42日龄空肠绒毛高度和绒毛高度/隐窝深度(P0.05)。4)饲粮添加50和100 mg/kg COS显著降低了回肠大肠杆菌数量(P0.05)。5)饲粮添加100 mg/kg COS显著提高了肉鸡的平均日增重(P0.05)。由此可见,饲粮添加COS可提高肉鸡抗氧化性能,改善肉鸡肉品质和肠黏膜组织结构,并在一定程度上改善肠道菌群结构。COS在肉鸡饲粮中的适宜添加量为100 mg/kg。  相似文献   

20.
1. This study examined responses of male broilers during a 42-d production cycle to two different rearing and feeding methods. 2. A total of 400 Chinese Yellow male broilers were allotted randomly at 21 d into two groups; the control was a typical indoor commercial rearing method and the treatment had outdoor access with scattered feeding (OS). Each group had 5 replicates with 40 birds per replicate. 3. Growth performance was similar for both groups from 21 to 63 d of age. OS birds had significantly lower abdominal fat percentage, meat shear force, drip loss, breast meat colour b* value and significantly higher pH value compared with the controls. OS birds had significantly lower muscle fibre diameter and greater muscle fibre density. Serum glutathione peroxidase and catalase activities were significantly higher and the contents of cholesterol, lactic acid, glycogen and malondialdehyde of breast muscle were significantly lower in OS birds than controls. 4. The results suggest that the OS feeding method had no negative effects on performance (weight, gain, feed conversion rate, carcase traits) compared with controls, and appeared to be beneficial for meat quality indices and oxidative stability.  相似文献   

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