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1.
The study was conducted to evaluate the response of broiler chicks to different dietary Na+ and Cl− concentrations with similar dietary electrolyte balance of 250 mEq/kg during 29 to 42 d of age in a hot environment with average minimum and maximum temperatures of 32.4 and 36.6°C, respectively, and an average RH of 69.2%. Three levels of dietary Na+ (0.20, 0.25, and 0.30%) and 3 levels of dietary Cl− (0.30, 0.40, and 0.50%) were used in 3 × 3 factorial arrangement in which BW at 28 d were used as covariate in the statistical analysis. A decreasing linear effect of dietary Na+ was observed on breast yield and lowering of abdominal fat, whereas increasing dietary Cl− linearly increased litter moisture and decreased dressing weights. No significant effects of dietary Na+, Cl−, or Na+ × Cl− were observed on feed intake, BW gain, feed:gain, rectal temperature, water:feed, or mortality. An improvement in litter condition, toe ash, blood parameters, and lowered abdominal fat yield was observed for the diet having 0.30% dietary Na+. The results of the present study suggest the dietary requirements of 0.20 to 0.25% Na+ and 0.30% Cl− during the finisher phase (29 to 42 d) of broiler chicks when the ambient temperature ranged from 32 to 40°C.  相似文献   

2.
Versazyme (VZ) is an approved keratinase-based feed additive produced naturally as a fermentation product of Bacillus licheniformis PWD-1. The experiment was designed to test the recovery and efficacy of VZ using typical feed industry pelleting parameters. The pelleted diets were conditioned to 85°C for 30 s and pelleted using a 4 × 32 mm die, cooled, and crumbled. A total of 192 male broiler chicks were fed a corn-soybean meal starter diet formulated at 18.5% CP to 21 d of age. The 4 treatments used in the feeding study were as follows: VZ 0.0%-mash, VZ 0.0%-pellet, VZ 0.1%-mash, and VZ 0.1%-pellet. Body weight and feed consumption were determined at 21 d of age. The recovery of VZ in feed was 93% in the mash diet and 66% in the pelleted diet. There was a 55-g increase in BW gain and 0.17 improvement of FCR when birds were supplemented with 0.1% VZ. Pelleting improved BW gain (P < 0.05) but did not significantly improve the FCR. Growth performance results indicate that pelleting did not affect the efficacy of VZ.  相似文献   

3.
This trial was performed to study the use of the mushroom Agaricus brasiliensis as an alternative additive to antimicrobial growth promoters in broiler chicken diets and to assess the quality of the broiler chicken breast meat of birds that are fed diets containing this fungus. Thus, 595 1-day-old chicks were reared in reused poultry litter without anticoccidial and antimicrobial additives. The results showed that a concentration of 1.6 g mushrooms/kg diet was ideal for these birds because it provided better bird performance. When the birds’ immune system organs were analyzed, it was found that the addition of both mushrooms influenced the immune system organs of these broiler chickens. Adding A. brasiliensis to broiler chicken diets did not compromise breast meat quality.  相似文献   

4.
Chopped switchgrass (SG) and chopped bermudagrass (BG) were evaluated as alternatives to pine shavings (PS) for broiler litter over 3 flocks. Twenty-four pens were filled with the 3 litter types. Live performance parameters included mortality, BW, BW gain, feed consumption, and feed conversion. Mortality was not different for litter type or flock. All other live variables were different (P < 0.0001) for flock. Mean foot pad scores (FPS) were only different (P < 0.0001) for flock. Litter performance variables included litter and cake moisture content (MC), pH, litter ammonia concentration, and cake nutrient values [nitrogen, phosphorus, and potassium (N–P–K)]. Litter and cake MC differed by litter type and flock (P < 0.0001). Litter MC was 1% lower for SG than BG or PS. Cake depth observations were similar for litter type. Litter pH differed by flock (P = 0.008) while cake pH differed for both litter type (P = 0.05) and flock (P < 0.0001). Beginning and ending litter ammonia concentration were different for flock (P < 0.0001). Potassium was different for both litter type (P = 0.04) and flock (P < 0.0001) while nitrogen and phosphorus differed only by flock (P < 0.0001). Chopped SG and BG performed as well as PS as a litter material over 3 grow-out cycles. Based on the results of this study, chopped grass materials appear to be a viable alternative to PS for broiler bedding.  相似文献   

5.
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   

6.
Illinois bundleflower (IBF; Desmanthus illinoensis) is a warm-season perennial legume native to the central plains of the United States and has potential as both a forage and grain crop. The objective of this research was to evaluate the potential of IBF seeds as a feed ingredient in broiler starter diets. One-day-old broiler chicks were fed 1 of 4 isocaloric and isonitrogenous experimental diets containing 0, 5, 10, or 15% IBF seed. Illinois Bundleflower seed is a high-protein (31.5% CP) feed ingredient with a Lys:Met similar to that of soybean meal. The TME content of IBF seed depends on the form in which it is fed. When fed ground, the TMEn content was determined to be 1,974 kcal/kg. When fed whole, with supplemental grit, the TMEn content was 1,067 kcal/kg. Inclusion of IBF seed in broiler starter diets had adverse affects on both feed consumption and BW gain, even at a 5% inclusion level. Further studies are required to determine whether IBF seed could be included in diets for older broiler chicks or laying hens.  相似文献   

7.
Among the reported probiotic Bacillus strains, B. subtilis C-3102 has the unique potential to improve feed uptake under stress conditions in the broilers, piglets, and cows. In this study, we sought to evaluate the protective effect of feed additive probiotic Bacillus subtilis C-3102 against Salmonella enterica infection of specific pathogen-free (SPF) chicks in floor pens in two experiments. In the experiment-1, the chicks in the control group (n=32) were fed a basal diet and those in the C-3102 group (n=32) were fed a basal diet supplemented with 1×106 CFU/g of feed for 28 days. On day 7 post-challenge with S. enterica, there was no significant change in the body weight between both the groups throughout the test period, whereas detection rates of S. enterica in the C-3102 group were significantly lower in the cecum and liver on days 21 and 14 post-challenge, respectively. In the experiment-2, minimum dosage of C-3102 cells required to protect Salmonella infection was evaluated using 3 dosages. Chicks were divided into four groups, fed with different dosages of C-3102 (1×106, 5×105, 3×105, and 0 CFU/g of feed), and challenged with S. enterica (2.8×108 CFU/chicken). S. enterica infection was completed within 7 days post- challenge and was almost excluded from the liver and spleen on day 21 post- challenge in the control group. Average values showed a trend for higher infection rates in the control group >3×105>5×105>1×106 CFU/g on days 14 and 21 post-challenge. These results suggest that B. subtilis C-3102 supplementation has the potential to reduce S. enterica infection rates and/or to accelerate the exclusion of S. enterica from the chicks.  相似文献   

8.

This study compared five commercially available probiotics vis-à-vis antibiotic growth promotant (AGP) supplementation and absence of feed additive based on efficiency, intestinal morphometry, and energy digestibility in improving broiler chicken production. A total of 630 straight run (Cobb) day-old broiler chicks were distributed to seven treatments following a completely randomized design, with ten replicates per treatment and nine birds per replicate per cage. Dietary treatments consisted of basal diet in combination with the following: without probiotics and AGP supplementation (treatment 1); 75 ppm each of chlorotetracycline (CTC) and Zn bacitracin (treatment 2); probiotic A, Bacillus subtilis (treatment 3); probiotic B, Bacillus subtilis (treatment 4); probiotic C, Enterococcus faecium (treatment 5); and probiotic D, Bacillus subtilis (treatment 6); probiotic E, Enterococcus faecium, Bifidobacterium spp., Pediococcus spp., and Lactobacillus spp. (treatment 7). At day 42, energy digestibility was determined by fasting three randomly selected birds from each treatment for 12 h and then subjecting them to their corresponding dietary treatments. Excreta were collected and pooled after 24 h of feeding. Pooled excreta were weighed, oven-dried, and subjected to energy analyses after 3-day collection. Apparent total tract metabolizable energy was then computed. At day 47, three birds were randomly selected per treatment for intestinal morphometry (villi height and crypt depth) of the duodenum, jejunum, and ileum. Dietary supplementation using probiotics showed no significant effect on overall body weight, weight gain, feed consumption, feed efficiency, dressing percentage, mortality, harvest recovery, carcass quality parameters (e.g., meat to bone ratio and abdominal fat content), intestinal morphometry, and energy digestibility. Birds under treatment 7 (basal feed + probiotic E) generated the highest income over feed and chick cost.

  相似文献   

9.
In an attempt to demonstrate the efficacy of Bacillus subtilis PB6, isolated from the gut of a healthy chicken, on broiler performance, an experimental trial was conducted in which broilers, infected or uninfected with a pathogenic strain of Escherichia coli, were supplemented with B. subtilis PB6 (CloSTAT) or zinc bacitracin-colistin sulfate and compared against negative controls given no antibiotic supplementation. We observed 10- and 8-point improvements in feed conversion ratio (FCR) in 42-d-old uninfected broilers treated with B. subtilis PB6 when compared with the negative and antibiotic controls, respectively. However, infected birds supplemented with B. subtilis PB6 registered a significant 15-point FCR improvement over those in the negative control group (P < 0.05). Compared with the negative control, the increase in body weights of uninfected and infected 42-d-old broilers receiving B. subtilis PB6 were 97 and 152 g, respectively (P < 0.05). The growth-promoting and protective results from this study indicated that B. subtilis PB6 not only helped in the maintenance of beneficial bacteria but also could act as a replacement for antimicrobial growth promoters in broilers. The percentages of mortality of infected birds within antibiotic-treated groups and B. subtilis PB6-treated groups were reduced from 14% to 6 and 8%, respectively. Numerically, uninfected birds supplemented with B. subtilis PB6 had elevated levels of lactobacilli (1.4 to 4.5 × 107 cfu/g) in their intestinal tracts (32- and 42-d-old broilers) compared with the controls. Even after being challenged with a pathogenic strain of E. coli, the lactobacilli counts in the B. subtilis PB6-treated birds tended to remain the same as those receiving antibiotic and were considerably higher than those of the untreated birds.  相似文献   

10.
The effect of used pine-shaving litter from broiler floor pens on Salmonella colonization resistance was evaluated in broiler chicks. One-day-old chicks were placed in floor pens on fresh unused litter or on used litter. All chicks were challenged orally with 10(4) S. typhimurium at 3 days of age. The study was replicated in three trials with used litter that was collected and stored for 1 day (Trial 1), 4 days (Trial 2), or 50 days (Trial 3) before the start of each trial. Cecal concentrations of volatile fatty acids (VFAs) were significantly higher (P < 0.05) in chicks placed on used litter than in chicks on new litter. In all three trials, the number of Salmonella in the cecal contents and the number of Salmonella cecal-culture-positive chicks was significantly lower (P < 0.01) at 10 days and 20 days of age in the chicks on used litter than in the chicks on new litter. The results indicated that newly hatched chicks reared on used litter had higher cecal VFA concentrations and higher resistance to Salmonella colonization than chicks reared on new litter.  相似文献   

11.
Two experiments were conducted with broiler chicks to determine the nutritive value of high-oil sunflower meal (HO-SFM), a sunflower oil extraction by-product obtained through screw-press extraction and expanding processes with a proximate composition of 32% CP, 12% crude fiber, and 19% ether extract. In Experiment 1, the effects of a high level (46.4%) of HO-SFM on chick performance and gastrointestinal organs were tested. The objective of Experiment 2 was to determine if pelleting the feed could overcome the bulkiness resulting from inclusion of HO-SFM at a high level. The results of Experiment 1 indicated that addition of 46.4% HO-SFM to broiler starter diets significantly (P < 0.05) depressed body weight, feed intake, and gain but not feed conversion. Fat pad and liver lipid were again significantly (P < 0.05) decreased in the HO-SFM treatment. Impaired performance might have been due to the difference of the density of HO-SFM diet (608 g/L) compared with the soybean meal control (723 g/L). When bulkiness was overcome by pelleting in Experiment 2, it was found that pelleting the feed significantly enhanced growth of broiler chicks compared with SFM or soybean meal mash diets. Liver weights and lipid content were again decreased in HO-SFM diets. The results of this study suggest that HO-SFM can be used up to 28% without adverse effects on broiler chicks. Further improvement was observed with pelleting. Liver weight and lipid content were consistently reduced by feeding HO-SFM.  相似文献   

12.
Currently, there is a need to investigate feed additive application strategies, especially those used in conjunction with live coccidiosis vaccines (LCV). The objective of this study was to determine the effects of the inclusion strategies of several commercially available feed additives using broilers sprayed with 10× live coccidiosis vaccines (LCV) throughout a 49 d grow-out. All birds received 10× LCV on d of hatch, excluding treatment (Trt) 1, the unmedicated negative control (NC). The positive control (PC; Trt 2), was also unmedicated, but birds were sprayed with 10× LCV. Birds assigned Trts 3 to 8 also received LCV, and diets consisted of the following additives: Virginiamycin (VA) at 20 g/t throughout with Salinomycin (SAL) at 40 g/t from d 14 to 28 (Trt 3); VA at 20 g/t throughout d zero to 49 (Trt 4); a Bacillus subtilis probiotic (PRO) with Bacitracin Methylene Disalicyalte (BMD) at 50 g/t from d zero to 49 (Trt 5); an herb and essential oil blend (EB) from d zero to 49 (Trt 6); BMD at 50 g/t throughout with an increased dose (200 g/t) from d 14 to 28 (Trt 7); and BMD at 50 g/t throughout with SAL (40 g/t) from d 14 to 28 (Trt 8). In general, birds fed Trts 3 and 7 demonstrated increased BW and BW gain when compared to those fed Trt 2 (NC). Birds fed Trt 5 exhibited similar d 49 BW to that of birds fed Trt 3 and 7 — however, better than those fed Trt 2. Of these Trts, birds fed Trt 3 demonstrated at d 17 increased ileal digesta viscosity and reduced lesion scores caused by Eimeria acervulina, although overall scores were low. Gastrointestinal organ measurements and morphology at d 17 were not significantly affected by Trt. Overall, these data suggest that feed additive strategies utilized in Trts 3, 5, and 7 are a viable option with using LCV.  相似文献   

13.
A study was conducted examining the effects of prebiotics and probiotics separately and in combination on growth parameters, fecal and cecal microbiota. Six dietary treatments consisted of: 1) control, 2) control + 0.2 lb/ton calculated to contain 1 × 1010Pediococcus acidilactici/kg, 3) control + 0.2 lb/ton calculated to contain 2 × 1010 live Saccharomyces cerevisiae boulardii/kg, 4) control + 2 lb/ton yeast cell wall extract (YCWE), 5) control + 0.2 lb/ton calculated to contain 1 × 1010 /kg Pediococcus acidilactici/kg and + 2 lb/ton YCWE, and 6) control + 0.2 lb/ton calculated to contain 2 × 1010/kg live Saccharomyces cerevisiae boulardii/kg + 2 lb/ton YCWE. Dietary treatments had 10 replicates during the brooder phase; 6 replicates from grower phase through conclusion of the study. Bovan white pullets were utilized for the study. There was not a significant difference between treatments for feed intake, body weight, body weight gain or feed conversion. There were no significant differences between treatments for Salmonella enteritidis presence or fecal counts of E. coli, coliform, and Salmonella spp. Cecal E. coli and coliform counts were not affected by treatment. There was a significant treatment by time effect for Enterobacteriaceae cecal counts. Enterobacteriaceae counts increased at 16 wk of age and decreased through the study for all treatments, except for YCWE. The addition of prebiotics and probiotics, individually or in combination, did not significantly improve growth or alter the potentially pathogenic bacteria microbiology of feces or ceca in pullet chicks.  相似文献   

14.
The objective of this study was to investigate the effect of dietary citric acid (CA) on the performance and mineral metabolism of broiler chicks. A total of 1720 Ross PM3 broiler chicks (days old) were randomly assigned to four groups (430 in each) and reared for a period of 35 days. The diets of groups 1, 2, 3 and 4 were supplemented with 0%, 0.25%, 0.75% or 1.25% CA by weight respectively. Feed and faeces samples were collected weekly and analysed for acid insoluble ash, calcium (Ca), phosphorus (P) and magnesium (Mg). The pH was measured in feed and faeces. At the age of 28 days, 10 birds from each group were slaughtered; tibiae were collected from each bird for the determination of bone mineral density, total ash, Ca, P, Mg and bone‐breaking strength, and blood was collected for the measurement of osteocalcin, serum CrossLaps®, Ca, P, Mg and 1,25(OH)2Vit‐D in serum. After finishing the trial on day 37, all chicks were slaughtered by using the approved procedure. Birds that were fed CA diets were heavier (average body weights of 2030, 2079 and 2086 g in the 0.25%, 0.75% and 1.25% CA groups, respectively, relative to the control birds (1986 g). Feed conversion efficiency (weight gain in g per kg of feed intake) was also higher in birds of the CA‐fed groups (582, 595 and 587 g/kg feed intake for 0.25%, 0.75% and 1.25% CA respectively), relative to the control birds (565 g/kg feed intake). The digestibility of Ca, P and Mg increased in the CA‐fed groups, especially for the diets supplemented with 0.25% and 0.75% CA. Support for finding was also indicated in the results of the analysis of the tibia. At slaughter, the birds had higher carcass weights and higher graded carcasses in the groups that were fed the CA diets. The estimated profit margin was highest for birds fed the diet containing 0.25% CA. Birds of the 0.75% CA group were found to have the second highest estimated profit margin. Addition of CA up to a level of 1.25% of the diet increased performance, feed conversion efficiency, carcass weight and carcass quality, but only in numerical terms. The addition of CA up to 0.75% significantly increased the digestibility of macro minerals, bone ash content, bone mineral density and bone strength of the broiler chicks. It may, therefore, be concluded that the addition of 0.75% CA in a standard diet is suitable for growth, carcass traits, macromineral digestibility and bone mineral density of broiler chicks.  相似文献   

15.
The efficacy of replacing broiler litter with rice mill feed was evaluated in four experiments. In Exp. 1, 40 predominantly Angus steers (initial BW = 277+/-18.2 kg) were fed four dietary treatments for 112 d (five steers per pen; two pens per diet). Dietary treatments (DM basis) were as follows: 1) 47% broiler litter:53% corn; 2) 60% rice mill feed:40% corn; 3) 50% rice mill feed:50% corn; and 4) 40% rice mill feed:60% corn. All diets, along with bermudagrass hay, were fed free choice. Daily gains were faster (P < 0.10) for the 50:50 and 40:60 diets (1.26 and 1.30 kg/d, respectively) than for the broiler litter diet (0.89 kg/d). Daily DMI was less (P < 0.10) by steers consuming rice mill feed-based diets than by those consuming broiler litter-based diets. In Exp. 2, 16 Angus x Charolais steers (initial BW = 277+/-22.7 kg) were fed the same four diets used in Exp. 1 while housed in individual metabolism stalls for determination of nutrient digestibility. Daily DMI was not different (P > 0.10) among diets. Nutrient digestibilities did not differ among diets (P > 0.10). In Exp. 3, 40 Continental cross steers (initial BW = 257+/-21.3 kg) were fed one of four dietary treatments for 112 d (five steers per pen; two pens per diet). On a DM basis, diets were as follows: 1) 47% broiler litter:53% soyhulls; 2) 70% rice mill feed:30% soyhulls; 3) 60% rice mill feed:40% soyhulls; and 4) 50% rice mill feed:50% soyhulls. All diets, along with bermudagrass hay, were fed free choice. Daily gains were less (P < 0.05) for the broiler litter diet than for the 60:40 and 50:50 diets (1.05, 1.16, and 1.28 kg/d, respectively), and steers fed the broiler litter diet consumed less DM than did steers fed the varying rice mill feed-based diets (P < 0.10). In Exp. 4, 16 Angus x Charolais steers (initial BW = 292+/-21.1 kg) were fed the same four diets as in Exp. 3 while housed in individual metabolism stalls for determination of nutrient digestibility. Daily DMI was less (P < 0.01) for the broiler litter diet (5.0 kg/d) than for the 70:30, 60:40, and 50:50 diets (7.8, 7.9, and 7.9 kg/ d, respectively). Digestibilities for DM, OM, and ADF did not differ (P > 0.10) among treatments; however, CP digestibility was greatest (P < 0.10) for the 60:40 diet, and NDF digestibility was least (P < 0.10) for the 70:30 diet. Rice mill feed can be used to replace broiler litter to formulate low-cost diets for stocker calves. Soyhulls and corn can be blended with rice mill feed to produce acceptable backgrounding diets for growing beef calves.  相似文献   

16.
Diets containing low-quality durum wheat (716 g/kg) for production of pasta were used to feed male broiler chicks. The efficacy of xylanase supplementation and the impact of xylanase inhibitors on losses in exogenous enzyme activity were analyzed. Birds fed on the basal diet, not supplemented with recombinant xylanases or Roxazyme G, reached a BW of 1,509 g with a feed conversion ratio of 1.77 at d 28. Growing performance was above that expected for the breed used, whereas feed conversion ratios were relatively higher. None of the 3 xylanase preparations under analysis affected growing performances and feed efficiency of broiler chicks. The activity of feed xylanases was considerably reduced in the presence of durum wheat extracts. The results suggest that reduction of exogenous enzyme activity was due to the action of durum wheat xylanase inhibitors and not to proteolysis.  相似文献   

17.
枯草芽孢杆菌制剂对肉鸡生长性能的影响研究   总被引：3，自引：0，他引：3  
研究了枯草芽孢杆菌制剂对肉鸡的生长性能和经济效益的影响。选用90羽7日龄的肉仔鸡,随机分成三个处理组,每个处理设三个重复。对照空白组饲喂基础日粮,抗生素组饲喂基础日粮加0.05%的硫酸新霉素制剂,试验组饲喂基础日粮加0.1%的枯草芽孢杆菌制剂。试验期35d。结果:试验组肉鸡的末期平均体重、净增重和日增重均高于空白对照组,差异显著(P<0.05),但均比抗生素组低,差异不显著(P>0.05)。试验组鸡的平均采食量均略高于两对照组(P>0.05),试验组的饲料转化率较空白对照组提高3.14%,比抗生素组低1.59%(P>0.05)。经济效益分析,试验组比空白对照组减少净增重耗料成本0.148元/kg,相对经济效益提高了3.48%;比抗生素组减少净增重耗料成本0.083元/kg,相对经济效益提高了1.98%。结果表明在较高的营养水平条件下添加制剂对肉鸡生长具有一定的促进作用,取得较好的饲料转化效率和经济效益,可以在肉鸡饲养整个期间替代抗生素添加剂。  相似文献   

18.
A trial was conducted to assess the effects of the dietary supplement Yucca schidigera extract on the performance of broilers subjected to different coccidiosis control methods. Six hundred male broiler chicks were randomly allocated to 1 of 5 treatments with 4 replicates each. The treatments were as follows: T1, vaccinated against coccidiosis; T2, nonvaccinated, a dietary coccidiostat; T3, vaccinated against coccidiosis, diet supplemented with Y. schidigera extract (0.01%); T4, coccidiostat plus Y. schidigera extract added to feed (0.01%); and T5, nonvaccinated, nonsupplemented control. The parameters analyzed were bird performance and morphology of the intestinal mucosal surface. The intestinal villi were higher at 6 d of age in broilers treated with coccidiostats or vaccinated against coccidiosis and supplemented with Y. schidigera extract compared with groups receiving the vaccine only or no treatment. Addition of the Y. schidigera extract to the diet of vaccinated birds improved average daily gain and feed conversion rate at 42 d of age compared with the other treatments, suggesting there might be a beneficial, synergistic effect between the coccidiosis vaccine and the Y. schidigera extract.  相似文献   

19.
A Box–Behnken design (BBD) in a response surface methodology (RSM) was used to investigate the response of broiler chicks to in ovo feeding (IOF) of beta‐hydroxy beta‐methylbutyrate (HMB), dextrin and the timing of the first water and feed deprivation. On day 18th of incubation, 1,500 eggs were randomly assigned to 15 experimental runs of BBD, each with 4 replicates, as 3 levels IOF of HMB (0%, 0.5% and 1%) and dextrin (0%, 20% and 40%), and 3 levels of the first water and feed deprivation (6, 27 and 48 hr). Day‐old chicks from each replicate were then used to assess the effect of IOF and time first water and feed access on chick's responses. The IOF of dextrin leads to respectively 9.7%–15.5% lower hatchability for 20% and 40% inclusion (p < .05), whereas HMB inclusion appeared with no effect on hatchability (p > .05). Administration of dextrin or HMB into the amnion of embryos elevated length, width and surface area of villus, and increased glycogen content of liver and breast (p < .05). In all parameter models, the linear terms showed highest contribution (R2 = 0.81–0.97) to explain existing variation in chick's responses. The first water and feed deprivation had largest effect on BW2 and glycogen content of liver and breast. It is concluded that if possible, place chicks before 7 hr of hatch to preserve BW loss and have maximum response from IOF. If not possible, use IOF with 40% dextrin + 0.5% HMB to preserve gut integrity and energy status up to 48 hr. This should give advantage to chicks to recover fast after feeding, but that would have to be confirmed by trials growing birds to slaughter age.  相似文献   

20.
Watering systems utilized in broiler production can impact bird performance. Many companies have increased water flow rates (WFR) in their nipple drinkers (ND) system during brooding above the manufacturers recommended level, then make adjustments in WFR during the grow period. This has increased moisture and early caking problems in litter. The objective of this study was to determine how birds perform on different WFR rates during brood and grow periods while observing litter condition. Seven WFR treatments were evaluated for broilers reared from 1 to 42 d age: 50 mL/min, 75 mL/min, 100 mL/min, 120 mL/min, 50 mL/min 1 to 7 d increasing to 75 mL/min 8 to 42 d, 75 mL/min 1 to 7 d increasing to 100 mL/min 8 to 42 d, and 100 mL/min 1 to 7 d increasing to 120 mL/min 8 to 42 d. Chicks were identified and randomly allocated in a randomized complete block design. BW, cumulative feed consumption (FC), FCR (feed:BW), litter moisture (%), and litter moisture under the ND were determined weekly to 42 d. Mortality (MO) was recorded daily. Birds tended to have heavier BW on d 35 when (P = 0.08) on the higher WFR (75, 100, and 120 mL/min) in comparison to birds on the lowest WFR (50 mL/min). No differences were observed for FC, FCR, or MO. Birds on treatments with higher WFR (100 and 120 mL/min) and treatments which were increased to higher WFR (75 to 100 mL/min and 100 to 120 mL/min) utilized greater amounts of water as compared to birds receiving lower WFR (50 and 75 mL/min). The 100 and 120 mL/min WFR resulted in higher percent litter moisture (P ≤ 0.01) under the ND but decreased at the end of the growing period. In conclusion, as birds become heavier, they attempt to utilize larger amounts of water from ND with greater WFR without any beneficial effect on bird performance. As WFR increase, litter moisture under the ND will initially increase but then decrease as the birds age.  相似文献   

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