Effect of wet feeding on growth performance of broiler chickens in a hot climate

1. The Guinea Savanna in the tropics is characterised by high diurnal temperatures, often beyond the thermo-neutral zone of modern poultry, which imposes heat stress on them. 2. An experiment was conducted to determine the effect of partially (12 h wet mash in the day and 12 h dry mash in the night) or wholly (24 h) feeding wet mash on the growth performance of broiler chickens. 3. Three treatments: dry mash (control), wet mash (day) + dry mash (night) and wet mash (day + night) were tested. At 28 d of age, a total of 120 broiler chickens (Hybro, Netherlands) were randomly divided, using a completely randomised design, into 12 groups of 10 birds, each with mean live weight of approximately 800 g/bird. A maize-soybean based grower mash (200 g CP/kg and 12·5 MJ/kg ME) was fed. The wet mash was prepared daily by addition of 1·3 parts of water to 1 part of dry mash and fed from 28 to 56 d of age. The birds were housed in raised-floor pens. Feed and water were given ad libitum and light provided 24 h. Mean daily room temperature was 28-29°C in the morning and 35-41°C in the afternoon. 4. Mean feed intake of birds fed the wet mash (174 g/day) or wet + dry mash (166 g/day) was higher than that of birds fed the dry mash (152 g/day). Mean live weight gain of birds fed the wet mash (64 g/day) or wet + dry mash (64 g/day) was higher than that of birds fed the dry mash (58 g/day). There were no differences in gain/feed ratios (0·38-0·39) of any of the treatments, neither were there any differences between the feeding of wet mash partly or wholly for all variables. 5. It was concluded that wet feeding, particularly during day-time, had the potential to improve growth performance of broiler chickens in a hot climate.     

Effect of intermittent feeding,structural components and phytase on performance and behaviour of broiler chickens

1. Two experiments were conducted to study the effect of intermittent feeding on performance and the efficacy of an exogenous phytase, and to assess whether intermittent feeding changed the activity pattern of broiler chickens.

2. Broiler chickens were given, either ad libitum or intermittently, a phosphorus deficient pelleted diet containing either coarsely or finely ground oat hulls and either no enzyme or a phytase added from 10 d of age, in a 2 × 2 × 2 factorial arrangement. Ad libitum feeding consisted of continuous access to feed in a room with 18 h of light and 6 h of complete darkness, whereas birds on intermittent feeding had restricted access to feed from 7 d of age, with 4 1-h feeding bouts/d and one 2-h feeding bout/d from d 14.

3. Performance, characteristics of the anterior digestive tract and phosphorus retention were assessed in experiment 1, while in experiment 2, birds were observed during 4-h periods to quantify different behaviours.

4. Intermittent feeding and phytase improved performance, but intermittent feeding did not improve the efficacy of the enzyme added. Ad libitum fed broiler chickens ate and drank on average twice per hour, and spent close to three-quarters of their time resting. Apart from an increased standing and feed searching activity for intermittently fed birds compared to ad libitum fed birds during the last hour before feed was presented, no differences in activity was detected.

5. It was concluded that broiler chickens quickly adapt to intermittent feeding without reduction in final body weight and with improvements in feed efficiency, but without improving the efficacy of dietary phytase. Only small changes occur in the behaviour of intermittently fed birds compared to ad libitum fed birds.     

Effect of feeding whole cereals on performance,starch digestibility and duodenal particle size distribution in broiler chickens

1. An experiment was conducted to study the effects of whole wheat, oats and barley at different inclusion levels on performance, starch digestibility, duodenal particle size distribution, gizzard weight and pH of gizzard contents for broiler chickens. 2. Feed consumption and weight gain were significantly reduced when ground cereals were replaced by whole cereals (P < 0.05). However, feed conversion efficiency was not affected by inclusion of up to 440 g/kg of whole wheat, and up to 300 g/kg of whole oats and barley. 3. Duodenal particle size was measured by laser diffraction to below 1 micron in size. A remarkably large proportion of particles were below 100 microns, with as much as 50% of the particles in the duodenum being below 40 microns in size. Inclusion of moderate amounts of whole cereals reduced the duodenal mean particle size. Large inclusions of whole cereals decreased (P < 0.05) the proportion of particles up to 40 microns in size, and increased (P < 0.05) the proportion with size between 100 and 300 microns. 4. Starch digestibility was improved (P < 0.05) by replacing ground wheat or barley with whole wheat or barley. 5. There was no consistent effect of cereal species or feed form on the pH value of the gizzard contents.     

Effects of body weight at, and lighting regimen and growth curve to, 20 weeks on laying performance in broiler breeders

1. A total of 4000 Ross broiler breeders were reared to a 20-week target body weight of 1.55, 2.16 (standard), 2.50 or 2.84 kg, using either a convex or concave growth curve. Each treatment group was either exposed to a conventional broiler breeder lighting regimen, with a series of weekly one-hour increments in photoperiod from 8h at 19 weeks to a 16-h maximum, or maintained from 4d on a 17-h photoperiod. 2. Each 100 g increment in body weight at 20 weeks was associated with a significant increase of 0.55 kg in cumulative food intake, and a 1.5-d advance in sexual maturity. However, leaner body weights at 20 weeks resulted in smaller body weight gains between 20 and 60 weeks (-2.4 g/d/kg body weight at 20 weeks), and an increased production of double-yolked eggs. Neither egg production nor mean egg weight was affected by 20-week body weight. 3. Birds fed to produce more rapid early growth had higher feed intakes to 20 weeks, but reached sexual maturity 7 d later than birds permitted accelerated growth from 15 weeks. Growth curve did not influence body weight gain in lay, egg production or mean egg weight. 4. Birds maintained on 17-h photoperiods reached sexual maturity 27 d later, produced 7 fewer eggs to 60 weeks, and had a mean egg weight 1.2 g heavier than birds photostimulated at 19 weeks. Lighting treatment did not affect food intake to 20 weeks, the proportion of double-yolked eggs or body weight gain between 20 and 60 weeks. 5. Birds fed to have a faster growth early in the rearing phase and maintained on 17-h photoperiods produced 11 fewer eggs than those fed to have accelerated growth at the end of the rearing phase, yet there was only one egg difference between the growth-curve groups for the conventionally lighted birds, which was not significant. 6. The earlier sexual maturity of the conventionally lighted birds compared with those maintained on 17-h photoperiods either indicates that broiler breeders require an increment in photoperiod to stimulate rapid gonadal development or that broiler breeders exhibit juvenile photorefractoriness that takes longer to be dissipated when birds are not given a period of short days. 7. The findings suggest that a nutritional stimulus late in rearing is only necessary for satisfactory egg production if birds have not received a concurrent increment in photoperiod.     

Effect of feeding diet with alternate protein sources and quality protein maize on performance and nutrient utilization in broiler chickens

Tropical Animal Health and Production - The experiment was conducted to study the effect of feeding diets with quality protein maize (QPM) along with cottonseed meal (CSM) and guar meal (GM) on...     

Effect of clinoptilolite on performance of broiler chickens during experimental aflatoxicosis

1. The amelioration of aflatoxicosis in broiler chickens was examined by feeding 2 concentrations of natural zeolite (clinoptilolite). Clinoptilolite (CLI), incorporated into the diet at 15 and 25 g/kg, was evaluated for its ability to reduce the deleterious effects of 2.5 mg total aflatoxin (AF; 76.40% AFB1, 16.12% AFB2, 6.01% AFG1 and 1.47% AFG in diet on growing broiler chicks from 1 to 21 d of age. A total of 360 broiler chicks were divided into 6 treatment groups (6 replicates of 10 broilers each): control, AF, CLI (15 g/kg), AF plus CLI (15 g/kg), CLI (25 g/kg), and AF plus CLI (25 g/kg). 2. Compared to controls, the treatment had significantly decreased body weight gain from week 1 onwards. The adverse effect of AF on food consumption (8.0%) and food conversion ratio (8.3%) was also shown over the entire 21-d feeding period. 3. The addition of CLI (15 g/kg) to an AF-containing diet significantly reduced the deleterious effects of AF on food consumption and body weight gain. Food conversion ratio was also slightly improved by adding CLI (15 g/kg) to AF-containing diets. Food consumption, body weight gain and food conversion ratio values were rendered numerically intermediate between AF and control groups by the addition of CLI (25 g/kg) to the AF-containing diet. 4. The addition of CLI (both 15 and 25 g/kg) to the AF-free diet did not produce any significant changes compared with the controls, except for decreased total food consumption in the CLI (25 g/kg)-alone group. 5. These results suggest that CLI (15 g/kg) addition effectively diminished the detrimental effects of AF on the values investigated. Also, the lower dietary concentration of CLI (15 g/kg) was more effective than the greater concentration against the adverse effects of AF on the variables investigated in this study.     

Influence of nutrient density and lighting regime in broiler chickens: Effect on antioxidant status and immune functiona

1.?The effects of nutrient density and lighting regime on oxidant status and immune function of broilers were investigated in a 2 × 4 experimental design (8 groups of 576 chickens).

2.?There were two nutrient densities: high (H) starter diet AME 13·39 MJ/kg, 230 g crude protein (CP)/kg: finisher 13·39 MJ/kg, 197 g CP/kg CP) and low (L) starter AME 12·03 MJ/kg, 208 g CP/k; finisher 12·14 MJ/kg, 183 g CP/kg C. The 4 lighting regimes were continuous (CL) 23L:1D, 20L:4D (12L:2D:8L:2D), 16L:8D (12L:3D:2L:3D:2L:2D) and 12L:12D (9L:3D:1L:3D:1L:3D:1L:3D). Blood and lymphoid organs were collected at d 21 and 42 for assay of antioxidant indices and immunity.

3.?Chickens fed low density diet had a higher Fabricius bursa weight (FBW). Low density diet tended (P = 0·089) to increase the a-Naphthylacetate esterase (ANAE) positive percentage response at 42 d.

4.?The 12L:12D schedule decreased serum malondialdehyde compared with other regimes at 21 d. At 42 d, it was lower in the 12L:12D and 16L:8D groups than in CL and 20L:4D. There was a trend (P = 0·086) for greater superoxide dismutase activity in the 12L:12D and 16L:8D groups than under the CL and 20L:4D regimes at 42 d. ANAE positive percentage in 12L:12D group at 42 d was higher than in CL and 20L:4D groups. Plasma IgG in the 12L:12D group at 42 d was higher than in the CL group.

5.?There was an interaction between nutrient density and lighting regime for FBW at 42 d.

6.?These results demonstrate that low nutrient density and a 12L:12D schedule lighting schedule can enhance oxidant-antioxidant balance and the immune functions of broilers.     

微胶囊化益生菌对肉鸡生产性能、抗氧化性能和免疫机能的影响

试验旨在研究微胶囊化益生菌对肉鸡生产性能、抗氧化水平和免疫机能的影响。选取1日龄爱拔益加(AA)肉仔鸡270只,随机分为3组(每组6个重复,每个重复15只)。对照组饲喂基础饲粮,益生菌组在基础饲粮中添加微胶囊(JM113活菌数为1×10^8 CFU/kg基础饲粮),抗生素组在基础饲粮中添加50 mg/kg金霉素,试验期42 d。结果表明:饲粮添加微胶囊化益生菌和抗生素显著提高了肉鸡平均日增重(P<0.05),降低了料肉比(P<0.05)。饲粮添加微胶囊化益生菌显著增加了肉鸡血清总抗氧化能力和总超氧化物歧化酶活性(P<0.05)。饲粮添加微胶囊化益生菌显著增加了肉鸡血清免疫球蛋白IgA、IgG和IgM水平(P<0.05)。由此可见,饲粮添加微胶囊化益生菌能取得与抗生素相同的促生长效果,并能提高肉鸡抗氧化能力和免疫水平。     

Effect of oat hulls on performance, gut capacity and feed passage time in broiler chickens

1. Two experiments were conducted to study effects of oat hulls and their interaction with soluble fibre in broiler chickens. 2. In experiment 1, wheat or naked oats based diets with or without NSP-degrading enzymes were mixed with 0, 40 or 100 g/kg oat hulls which replaced a maize starch/soy isolate mixture, and the diets were fed to broiler chickens from 7-21 d of age. 3. Production results, AMEn determined between 14 and 16 d of age, and ileal digestibility indicated no negative effect of oat hulls on nutrient digestibility or weight gain. 4. Feed consumption increased significantly when oat hulls were included in the diet and relative gut weight increased correspondingly (P<0.05). 5. No interaction effects were found between soluble and insoluble fibres, except for a possible effect on starch digestibility in wheat diets. 6. In experiment 2, mash diets were fed unsupplemented, or were supplemented with coarsely or finely ground oat hulls which replaced a maize starch/soy isolate mixture. 7. Faecal titanium dioxide excreted between 1 and 48 h after feeding of a gelatin capsule containing titanium dioxide, was used to calculate feed passage time. 8. There was a tendency (P=0.08) for faster feed passage with inclusion of coarsely ground oat hulls, but no effect of finely ground oat hulls was found.     

Effect of different non-chloride sodium sources on the performance of heat-stressed broiler chickens

1. One hundred and eighty 1-d-old broiler chicks were used to evaluate the effect upon broiler performance during severely hot summer months of three different sodium salts: sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3) and sodium sulphate (Na2SO4), in starter and finisher diets having an identical electrolyte balance (DEB) of 250 mEq/kg. 2. The non-chloride sodium salts were added to contribute the same amount of sodium and were substituted at the expense of builder's sand in the basal diets containing common salt (NaCl) as Na and Cl source. 3. Each diet was fed to three experimental units having 15 chicks each until 42 d of age. Severe heat-stress conditions, maintained in the rearing room, were indicated by high average weekly room temperature (minimum 29.3 degrees C; maximum 38.0 degrees C). 4. Diets containing sodium salts gave better body weight gain, feed intake and feed to gain ratio than the control diet. Sodium salts also enhanced water intake as well as water to feed intake ratio. This effect was more pronounced in broilers fed NaHCO3 supplement (with NaCl in the basal diets). 5. The increased water intake resulted in lower body temperature in heat-stressed birds fed NaHCO3 supplemented diet than in birds fed other sodium salts. A lower mortality rate was noted with NaHCO3 (15.15%), Na2CO3 (13.64%) and Na2SO4 (15.15%) supplements than with the control (33.33%) treatment. 6. Better carcase and parts yield were observed in sodium supplemented broilers. Sodium salts reduced the alkalotic pH and enhanced the blood sodium content, which ultimately improved the blood electrolyte balance and overall performance of heat-stressed broilers. 7. Supplementing broiler diets with sodium salts improved the live performance of heat-stressed broilers and better productive performance was noted with NaHCO3 than other sodium supplements.     

Effects of feeding deoxynivalenol contaminated wheat on growth performance, organ weights and histological parameters of the intestine of broiler chickens

A feeding trial was conducted to evaluate the effects of moderate dietary concentrations of deoxynivalenol (DON) during a 21-day feeding experiment on the performance of broilers. Fifteen 1-day-old broiler chicks were randomly divided into two groups. The control group was fed non-contaminated diet. Another group of broilers was fed a diet naturally contaminated with 5 mg DON/kg diet. Deoxynivalenol had no effect (p > 0.05) on feed consumption, feed conversion, body-weight gain, live body weight or mortality. The absolute and relative weight of the organs (gizzard, pancreas, heart, spleen, colon and caecum) were not altered by the dietary inclusion of DON contaminated grain. However, both the absolute and relative weight of small intestine was decreased (p < 0.01) in DON fed broilers compared to the controls. No gross lesions were detected in any of the organs of birds fed contaminated wheat during the feeding trial. The microscopic examination revealed that, the height and the width of villi in duodenum decreased (p < 0.05) in birds fed DON contaminated wheat compared to controls. On the other hand the height and the width of jejunum villi were not affected (p > 0.05). This study indicates that feeding DON for 21 days to broiler chickens at a concentration of up to 5 mg/kg of diet influenced the weight of the small intestine as well as intestinal histology, especially the duodenum, as evidenced by shorter and thinner villi. In conclusion, diets with DON contamination below levels that induce negative impact on health and performance could affect small intestinal morphology in broilers.     

Effect of dietary phosphorus concentration and electrolyte balance on the growth performance of broiler chickens

The performance of 1680 male and female broiler chickens given diets with either a low (4.7-4.3 g/kg) or high (8.9-8.2 g/kg) content of inorganic phosphorus and four (150, 200, 250 and 300 mEq/kg) electrolyte balances (Na+K-Cl) was measured from 1-d-old to 49 d of age. Diets with the higher concentration of inorganic phosphorus reduced body weight gains in the starter (P less than 0.01) and finisher (P less than 0.05) phases but the efficiency of food utilisation was reduced only in the starter phase (P less than 0.05). The reduction in body weight gain was greater in males than in females. The growth depression caused by the higher concentration of inorganic phosphorus in the finisher diets was partially alleviated by increasing the electrolyte balance to either 250 or 300 mEq/kg diet. The higher concentration of inorganic phosphorus significantly reduced the dressing percentage and increased the abdominal fat pad weight and litter moisture content. Electrolyte balance had no significant effects on efficiency of food utilisation, abdominal fat pad weights or litter moisture content. Neither the dietary concentration of phosphorus nor the electrolyte balance had a significant effect on mortality or ash content of the tibia.     

功能性饲料添加剂复方制剂对肉鸡生产性能和脂肪代谢的影响

本试验观察了一种功能性饲料添加剂复方制剂对肉鸡生产性能和脂肪代谢的影响。试验结果表明,在基础日粮中添加该复方制剂500mg·Kg-1可使49日龄肉鸡体重提高5.83%,料重比降低8.48%,成活率提高7.03个百分点;并同时降低肉鸡血清总胆固醇含量、血清甘油三酯含量、腹脂率和肝脏粗脂肪含量,而对胸肌粗脂肪含量无明显影响。