Effects of dietary fiber and threonine on performance,intestinal morphology and immune responses in broiler chickens

The present experiment was conducted to investigate the effects of fiber and threonine (Thr) on growth performance, intestinal morphology and immune responses of broiler chickens. A total of 420 one-day-old mixed sex broiler chicks (Ross 308) were randomly divided into 6 experimental diets and 5 replicates of 14 chicks based on a factorial arrangement (2 × 3) from 1 to 42 d of age. Experimental factors included dietary supplemental fiber type (no supplemental fiber [NSF], 30 g/kg sugar beet pulp [SBP] or 30 g/kg rice hull [RH]) and Thr inclusion level (100% or 110% of Thr requirement recommended by breeder company [Ross 308]). Growth performance of broilers was assayed at different periods of the experiment. Intestinal morphometric features were measured at 21 d of age. Antibody titer against sheep red blood cells (SRBC), Newcastle and influenza disease viruses were measured on d 30 of trial. Dietary inclusion of SBP and RH significantly decreased feed intake and weight gain during the entire rearing period (P < 0.05). Interaction of fiber and Thr had no beneficial effects on the performance of chickens across the entire rearing phase. Dietary supplementation of 110% Thr required level improved jejunal morphometric features (P < 0.05), whereas its inclusion with fibrous materials failed to show the same effects. Dietary supplemental Thr together with SBP significantly increased antibody production against SRBC (P < 0.05). In conclusion, although supplemental 30 g/kg fibrous materials impaired growth performance, inclusion of SBP along with 110% Thr level improved the humoral immunity in broiler chickens.     

蛋氨酸形式和饲粮蛋白质水平对黄羽肉鸡生产性能的影响

选用1日龄快长型岭南黄羽肉鸡公雏1500只,随机分为5个处理,每处理6个重复,每重复50只鸡,分别饲喂以下5种饲粮:正常蛋白质加Alimet饲粮(处理1)、正常蛋白质加DLM饲粮(处理2)、低蛋白质(比正常水平降低约1.5个百分点)加Alimet饲粮(处理3)、低蛋白质加DLM组饲粮(处理4)、正常蛋白质未加蛋氨酸饲粮(处理5)。结果表明,在等摩尔量有效成分添加基础上,Alimet比DLM更有利于提高黄羽肉鸡生长性能,降低饲料成本和死亡率;饲粮蛋白质水平和蛋氨酸形式对43～63日龄和0～63日龄黄羽肉鸡生长性能的影响存在互作效应,表现为在正常蛋白质水平时添加Alimet对黄羽肉鸡生长性能的改善效果优于DLM,且更有利于降低饲料成本,而在低蛋白质水平时添加Alimet和DLM则无显著差异;在本试验条件下,降低饲粮蛋白质水平会对黄羽肉鸡的生长性能、饲料成本和成活率产生不利影响。     

Effect of dietary lysine to crude protein ratio on performance of male Ross 308 broiler chickens

Two experiments were conducted to determine the effect of dietary lysine to crude protein ratio on performance of male Ross 308 broiler chickens. In each experiment the diets were isocaloric and isonitrogenous but with different lysine to crude protein ratios. A complete randomized design was used in both experiments, the starter (1–21 days) and grower (22–42 days) experiments. The three starter diets, based on lysine to crude protein ratios, were L₀ (0.055), L₁ (0.066) and L₂ (0.077), while grower diets were L₃(0.047), L₄(0.061) and L₅(0.074). A quadratic type equation was used to determine ratios for optimum growth rate, feed conversion ratio, breast meat yield and breast meat nitrogen content. Dietary lysine to crude protein ratios of 0.066 and 0.077 supported optimum growth rate and feed conversion ratio, respectively, during the starter period. Dietary lysine to crude protein ratios of 0.073, 0.073, 0.069 and 0.079 supported optimum growth rate, feed conversion and breast meat yield and nitrogen content during the grower phase. Dietary lysine to crude protein ratio had no effect on diet intake and digestibility. The results indicate that at each phase a single dietary lysine to crude protein optimized both growth rate and feed conversion ratio. However, the ratio for optimum breast meat yield was lower than that for optimum growth rate and feed conversion ratio. These findings have implications on ration formulation for broiler chickens.     

马齿苋粉对肉鸡生长性能和抗氧化能力的影响

文章旨在研究饲粮中添加马齿苋粉对肉鸡生长性能和抗氧化能力的影响。试验选取平均体重接近的1日龄AA肉鸡160只,称重后随机分为4组,试验1、2、3组在对照组饲粮的基础上分别添加0.30%、0.60%、0.90%的马齿苋粉,共处理42 d。结果发现,与对照组相比,肉鸡21日龄时,试验1、2、3组ADG分别增加5.5%、10.0%、6.8%(P <0.05),试验1、2组F/C分别降低8.2%、6.4%(P <0.05);42日龄时,试验1、2、3组ADG分别增加8.9%、9.6%、8.7%(P <0.05),F/C分别降低8.6%、9.6%、10.1%(P <0.05)。此外,21日龄时,试验1、2、3组肉鸡血清中T-AOC比对照组分别增加12.0%、14.4%、10.1%(P <0.05),T-SOD活性分别增加6.6%、10.5%、9.1%(P <0.05),MDA浓度分别降低6.3%、8.0%、5.6%(P <0.05);42日龄时,试验1、2、3组肉鸡血清中T-AOC比对照组分别提高13.9%、20.3%、13.6%(P <0.05),T-SOD活性分别提高10.5%、14.8%、9.5%(P <0.05),MDA浓度分别降低11.1%、14.9%、9.7%(P <0.05),试验1、2组血清中GSH-Px活性较对照组分别提高10.2%、11.8%(P <0.05)。结果表明,饲粮中添加马齿苋粉显著促进肉鸡生长及增强抗氧化能力。     

Effects of dietary supplementation of choline and carnitine on growth performance,meat oxidative stability and carcass composition of broiler chickens fed diets with different metabolisable energy levels

1. This study was conducted to investigate the effects of two lipotropic factors (choline and carnitine) on growth performance, oxidative stability of leg and breast muscles and carcass characteristics in broiler chickens fed diets differing in metabolisable energy (ME) levels.

2. A total of 540 one-d-old Ross 308 broiler chicks were allotted to 9 experimental diets, including three ME levels (control, or 0.42 or 0.84 MJ/kg higher ME) and three types of supplemental lipotropic factors (control, 1000 mg/kg of choline or 100 mg/kg of carnitine) as a 3 × 3 factorial arrangement of treatments. Average daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio (FCR) were recorded during the starter (1–14 d of age), grower (15–28 d of age) and finisher (29–42 d of age) periods.

3. Results showed that the increase in dietary ME level had no impact on ADFI during the starter and grower periods. In the finisher period, increasing dietary ME decreased (P < 0.001) ADFI. Raising dietary ME level by 0.84 MJ/kg resulted in the greater ADG during the grower (P < 0.05) and finisher (P < 0.001) periods. Moreover, an improvement in FCR was observed with feeding the +0.84 MJ/kg diet. Dietary supplementation of lipotropic factors improved FCR values in birds fed the control and +0.84 MJ/kg diets during the grower and finisher periods (P < 0.01).

4. Dietary supplementation of both choline and carnitine increased (P < 0.05) moisture content of leg muscle, although malondialdehyde content of leg muscle was decreased (P < 0.01) in the presence of both lipotropic factors. Dietary supplementation of carnitine decreased (P < 0.01) leg fat content, and this effect was more obvious with higher ME levels, giving a significant ME × lipotrope interaction (P < 0.05). Higher dietary ME level (+0.84 MJ/kg) reduced (P < 0.05) protein content of breast muscle, but this factor was increased (P < 0.05) by dietary supplementation of choline.

5. Although dietary ME level had no marked effect on carcass yield and internal organ weight, supplemental choline increased (P < 0.01) carcass yield.

6. The results from this trial indicated that dietary supplementation with lipotropic factors can improve feed efficiency in high energy diets. In addition, oxidative stability of leg/breast muscles was improved as a result of dietary supplementation with choline or carnitine.     

Effect of clenbuterol on growth,carcase and skeletal muscle characteristics in broiler chickens

1. Male and female broiler chickens (144 in total) were given diets supplemented with clenbuterol (CB) at 0 (control) and at 1 mg/kg between 28 and 49 d of age to study the effect of CB on growth, carcase and skeletal muscle.

2. CB improved growth in males by increasing daily weight gain and final live weight and by lowering food conversion ratio. In females it changed the carcase composition by reducing abdominal fat pad and by increasing the proportion of protein. Consequently, carcase protein gain was increased in both sexes (11% and 16%, respectively).

3. Skeletal muscle weights were enhanced by between 6% and 22%. Muscle fibre diameters were increased in extensor hallucis longus (EHL) but not in gastrocnemius (GAS) muscle. This increase was more pronounced in females. EHL total muscle fibre number remained unchanged. The proportion of fast‐twitch glycolytic fibres was increased at the expense of fast‐twitch oxidative fibres in males only. Nuclear/cytoplasm and DNA/protein ratios tended to be decreased by CB.

4. From the elevated EHL muscle RNA/DNA, unchanged protein/RNA and translation activity it is suggested that CB stimulated protein synthesis at the pretranslational level. Reduced protein degradation is deduced from decreased neutral calcium‐dependent proteolytic activity.

5. It is concluded that broiler chickens respond to long‐term CB treatment as has been shown in various mammals. However, the sex‐specific response in growth, carcase composition and skeletal muscle cellularity is more clearly apparent in broiler chickens.     

Growth performance and carcase quality in broiler chickens fed on bacterial protein grown on natural gas

1. The effects of increasing concentrations (0, 40, 80 or 120 g/kg) of bacterial protein meal (BPM) and bacterial protein autolysate (BPA) grown on natural gas on growth performance and carcase quality in broiler chickens were examined. 2. Adding BPM to diets reduced feed intake and improved gain: feed from 0 to 21 d and overall to 35 d, but did not significantly affect weight gain compared to the soybean meal based control diet. 3. Increasing concentrations of BPA significantly reduced growth rate, feed intake, gain: feed, carcase weight and dressing percentage, but significantly increased carcase dry matter, fat and energy content. 4. Adding BPM to diets had no effect on viscosity of diets and jejunal digesta, and minor effects on litter quality, whereas BPA increased the viscosity of diets and jejunal digesta, improved litter quality at 21 d, but decreased litter quality at 32 d. 5. To conclude, broiler chickens performed better on a BPM product with intact proteins than on an autolysate with ruptured cell walls and a high content of free amino acids and low molecular-weight peptides.     

饲粮中添加黄芩提取物对肉鸡生长性能、营养物质消化率和肉质的影响

文章旨在研究饲粮中添加黄芩提取物对肉鸡生长性能、营养物质消化率和肉质的影响。试验选取平均体重接近的1日龄AA肉鸡100只,称重后随机分为4组,试验1、2、3组在对照组基础饲粮基础上分别添加0.02%、0.04%、0.06%的黄芩提取物,处理42 d。试验结果:与对照组相比,试验2、3组肉鸡21日龄体重分别显著提高10.5%、9.3%(P<0.05),试验1、2、3组肉鸡42日龄体重分别显著提高8.7%、11.9%、10.4%(P<0.05)。1~21日龄,试验2、3组肉鸡ADG分别显著提高11.2%、10.0%(P<0.05);22~42日龄,试验1、2、3组肉鸡ADG分别显著提高9.5%、12.5%、10.9%(P<0.05),试验2、3组FCR分别显著降低12.7%、8.2%(P<0.05);1~42日龄,试验1、2、3组肉鸡ADG分别显著提高8.8%、12.2%、10.7%(P<0.05),试验2、3组FCR分别显著降低11.0%、7.8%(P<0.05)。试验1、2、3组肉鸡对饲粮中氮的消化率较对照组分别显著提高8.2%、9.8%、7.5%(P<0.05),试验2、3组肉鸡对GE的消化率分别显著提高8.5%、7.3%(P<0.05),试验2组肉鸡对饲粮中DM的消化率提高8.0%(P<0.05)。试验1、2、3组肌肉第5天的滴水损失较对照组分别显著降低14.9%、15.7%、15.2%(P<0.05)。表明,黄芩提取物可以促进肉鸡生长,改善养分消化率和肉质,添加量为0.06%时效果最好。     

Effects of dietary supplementation of emulsifier and carbohydrase on the growth performance,serum cholesterol and breast meat fatty acids profile of broiler chickens

A total of 540 2‐day‐old male Ross 308 broilers were used in a 35‐day experiment and were randomly divided into five treatments: (i) NC (low energy); (ii) PC (high energy diet); (iii) P1 (NC + 0.1% carbohydrases); (iv) P2 (NC + 0.05% emulsifier); and (v) P3 (NC + 0.1% carbohydrases + 0.05% emulsifier). From days 0 to 21, body weight gain in PC and P3 treatments increased (P < 0.05) compared with NC treatment. The chicks fed PC, P1, P2 and P3 improved (P < 0.05) feed conversion ratio compared with the NC treatment throughout the whole experiment. Abdominal fat weight was heavier (P < 0.05) in PC, P2 and P3 treatments than in NC and P1 treatments. On day 35, serum total cholesterol and low density lipoprotein cholesterol concentration were higher (P < 0.05) and high‐density lipoprotein cholesterol was lower (P < 0.05) in NC and P2 treatments than in PC, P1 and P3 treatments. The concentration of oleic acid, linoleic acid and total unsaturated fatty acids were highest (P < 0.05) in PC than in the other treatments. In conclusion, the results indicate that low energy density diet had lower growth performance, while the inclusion of emulsifier and carbohydrases in low energy diets can partially improve growth performance.     

Reduction of dietary crude protein and feed form: Impact on broiler litter quality,ammonia concentrations,excreta composition,performance, welfare,and meat quality

Nitrogen(N) excreted by poultry is converted to ammonia(NH₃), presenting an environmental risk and a health risk to the farmer and animals. A study was performed to investigate the effect of reduced CP and feed form on broiler performance and welfare, meat and litter quality, N utilization, and NH₃concentrations at litter level. A total of 2,232 Ross 308 male broilers was divided into 6 treatments and 6replicates, which was fed diets in both pellet and mash forms with diffe...     

Effect of dietary protein content on growth and body composition of fast and slow feathering broiler chickens

1. Broilers were produced from two lines of breeders selected for three generations for fast and slow feather growth. The base population foundation stock originated from a commercial pedigree female line, which carried only the dominant sex‐linked late feathering gene K. Three isoenergetic (12.7 MJ AME/kg) starter and grower diets were formulated to contain 280, 240 and 200, and 260, 220 and 180 g/kg protein, respectively, and fed to 156 broilers of each sex to give three starter‐grower combinations.

2. Broiler performance in terms of growth, food conversion ratio, carcase meat, fat and protein content was optimised on the 240 to 220 g/kg protein starter‐grower series of diets.

3. Birds of the slow line were significantly (P<0.05) heavier at 48 d of age and had the same food intake and food conversion ratio as birds of the fast feathering line.

4. The slow line birds had significantly (P<0.01) shorter feathers and less total plumage weight at 48 d. The slow line birds had significantly (P<0.001) less carcase fat and significantly (P<0.05) more carcase protein than the fast line. The slow line had significantly more carcase meat (P<0.01) within which a greater breast meat yield was evident (P<0.001).     

Effects of chitosan on growth performance and energy and protein utilisation in broiler chickens

1. Two experiments were conducted to investigate the effects of dietary chitosan on growth performance, energy availability and protein retention in broilers. 2. Experiment 1 was a 42-d growth assay, in which 294 1-d-old male broilers were given one of 7 dietary treatments. A control feed was supplemented with 5 levels of chitosan (0.2, 0.5, 1.0, 3.0 and 5.0 g/kg) or 50 mg/kg chlortetracycline (CTC). 3. Increasing chitosan inclusion gave a nonlinear increase (P< 0.001) in feed conversion efficiency (FCE). Optimal growth and feed conversion were obtained with 0.5-1.0 g/kg chitosan. 4. In experiment 2, 42 1-d-old male broilers (6/treatment) were individually housed but fed on the same diets as in experiment 1. Excreta were collected from d 19-21 and d 40-42. 5. The addition of 0.5-1.0 g/kg chitosan increased nitrogen retention compared with the control group (P< 0.01), while apparent metabolisable energy in the diets was not altered.     

Effects of dietary spirulina on meat colour in muscle of broiler chickens.

1. The present study was undertaken to determine the effects of dietary spirulina on growth performance and pigmentation in the muscle of growing broiler chickens and to examine the possibility that zeaxanthin in spirulina may affect yellow colour development in the meat. 2. Twenty-four, 21-d-old, male broiler chicks were fed an experimental diet containing spirulina at 0, 40, or 80 g/ kg for 16 d. No significant differences among treatments were observed in body weights, nor weights or yields (as a percentage of body weight) for any of the selected traits, including liver, abdominal fat, kidney and Pectoralis profundus. 3. Spectrocolourimetric analyses revealed that the redness of Pectoralis superficialis, profundus and Sartorius muscles reached a maximum in chicks fed the 40 g/kg spirulina diet, while the yellowness of all fillets, including the Semitendinosus muscle, increased in a sub-linear fashion with increased spirulina in the diet. The overall correlation between the yellowness and zeaxanthin content in the Pectoralis muscle was significant. 4. This study provides the first conclusive evidence that dietary spirulina influences both the yellowness and redness of broiler flesh and that the increments in yellowness with dietary spirulina content may possibly be reflected in the common yellow pigment related to the accumulation of zeaxanthin within the flesh.     

Effect of dietary protein and environmental temperature on growth performance and water consumption of male broiler chickens

1. Male broilers were reared in individual cages from 23 to 44 d of age. The effect of 2 temperatures (22° and 32°C) and 2 crude protein (CP) levels (160 and 200 g/kg) were studied. The low protein diet was supplemented with lysine, methionine, arginine, threonine and valine in order to meet requirements.

2. At 22°C, a reduced CP content did not affect growth rate and breast muscle but slightly increased adiposity and food to gain ratio (FCR). Water consumption was reduced.

3. High temperature reduced growth rate and absolute and proportional breast muscle weight, and increased adiposity and FCR. These effects were more pronounced with the low CP diet. Water consumption was also reduced.

4. It was concluded that reducing CP content did not seem a good way to help broilers to withstand hot conditions. This experiment suggests that amino acids other than lysine, methionine and cystine are probably involved in the detrimental effect of high temperature.     

Influence of activity and dietary energy on broiler performance,carcase yield and sensory quality

1. A total of 2560 male and female Ross broilers were raised to 42 days of age in a 2 × 2 treatment factorial arrangement experiment to investigate the influence of different degrees of physical activity and dietary energy on broiler performance, abdominal fat content, carcase yield and sensory quality.

2. Vertical fans were used to force the treatment birds to walk 3 to 4 times as far as the normal activity birds; birds were fed a normal and a high energy diet (12.55 compared with 13.81 MJ ME/kg) with the same energy/protein, energy/lysine and energy/methionine + cystine ratios.

3. High activity birds had greater body weight ( + 4.1%), food intake ( + 5.1%) and ME intake ( + 5.1%) than normal activity birds. Birds receiving high energy diet had a lower food conversion and food intake than birds receiving normal energy diet. There were no significant differences in body weight or ME intake between birds with different diets.

4. Slaughter yields, both absolute and relative to live body weight, were affected by activity or dietary energy to varying degrees. Breast meat was increased with more activity. The absolute weight of abdominal fat was independent of activity and in males the relative weight of abdominal fat was decreased in high activity birds.

5. Different degrees of activity and dietary energy had only minor influences on broilers' sensory quality.     

Effect of conjugated linoleic acid on growth performances, carcase composition, plasma lipoprotein lipase activity and meat traits of chickens

1. The effects of dietary conjugated linoleic acid isomers (CLAs) on productive traits, carcase yield and meat quality were investigated in Beijingyou (Chinese) chickens. A total of 360 male chicks were allocated to 5 dietary treatments (0.00, 0.25, 0.50, 1.00 and 2.00% CLA) and fed for 126 d. 2. The results showed that CLA supplementation did not significantly influence body weight, but increased feed conversion and decreased intramuscular fat in breast and thigh muscles. Mortality was significantly higher in the control group. 3. The addition of 1.0 and 2.0% CLA decreased abdominal fat percentages. At CLA dietary levels greater than 0.5%, lipoprotein lipase activity in plasma was significantly decreased. 4. Hunter L* and a* values were not significantly affected by CLA supplementation. However, Hunter b* values were lower in chickens supplemented at levels greater than 0.5% CLA. Supplementing diets with CLA modified the fatty acid composition of breast muscle. The proportions of CLA, saturated and polyunsaturated fatty acids were increased whereas the proportion of monounsaturated fatty acids was decreased.     

Effects of dietary supplementation with carnosine on meat quality and antioxidant capacity in broiler chickens

1. This study aimed to investigate the effects of carnosine supplementation on meat quality, antioxidant capacity and lipid peroxidation status in broiler chickens.

2. A total of 256 1-d-old male Arbor Acres broilers were randomly assigned to 4 treatments consisting of 8 replicates of 8 chickens each. The birds were supplied with 4 different diets: a basal diet or a basal diet supplemented with 100, 200 or 400 mg/kg carnosine, respectively. The whole experiment lasted 42 d.

3. The results showed that dietary supplementation with carnosine linearly increased the values of pH_45 min and redness and reduced drip loss of breast meat. Dietary carnosine increased the activity of antioxidant enzymes in liver, serum and breast meat and decreased the contents of lipid peroxides at 21 and 42 d of age.

4. These findings indicated that dietary supplementation with carnosine was beneficial to enhance meat quality, antioxidant capacity and decrease lipid peroxidation status of breast meat.     

Effects of dietary essential oil components on growth performance,digestive enzymes and lipid metabolism in female broiler chickens

1. The present experiment was conducted to describe the effects of thymol, cinnamaldehyde and a commercial preparation of essential oil components (CRINA Poultry), in female broilers. Feed and water were provided for ad libitum consumption. 2. Feed intake, weight gain and feed:gain ratio were not different among the treatments. Water intake was significantly lowered by cinnamaldehyde. Relative liver weight (g/100 g of body weight) was highest in birds given thymol, but this was seen only at the age of 21 d and not at 40 d. Patterns of digestive enzymes in pancreatic tissue were similar for the 4 treatments. 3. Amylase activity in intestinal digesta was highest in chickens given CRINA Poultry for 21 d, but the effect had disappeared after 40 d. Ileal digestibility coefficients for starch and protein were high and identical for all treatments. 4. Fatty acid composition of diet was reflected in that of adipose tissue. Plasma lipid concentrations were not changed by any dietary treatment. 5. Thus, the present results show no effect of essential oil constituents on growth performance in female broiler chickens, but it cannot be excluded that positive effects would have been observed under less hygienic environmental conditions or when using a less digestible diet.     

Effects of alpha-lipoic acid supplementation in different stages on growth performance,antioxidant capacity and meat quality in broiler chickens

1. This experiment was conducted to investigate the effect of basal dietary supplementation with 500 mg/kg alpha-lipoic acid (LA) on growth performance, antioxidant capacity and meat quality in different stages in broiler chickens.

2. A total of 240 Arbor Acre chickens were randomly assigned into 4 treatment groups, each treatment containing 6 replicates of 10 chickens each. Group 1 was the control group without LA supplementation; Group 2 was supplied with LA in the starter period; Group 3 was supplied with LA in the grower period; and Group 4 was supplied with LA in the whole period.

3. The results showed that LA supplementation improved average feed intake and body weight gain in all three experimental groups, especially in Group 2. LA supplementation significantly decreased abdominal fat yield in Groups 3 and 4.

4. LA supplementation all improved hepatic total antioxidant capacity, the level of glutathione, the activities of total superoxide dismutase, catalase (CAT) and glutathione peroxidase, in particular in Group 4. LA supplementation decreased the activity of liver xanthine oxidase (XO) in all experimental groups, and that of liver monoamine oxidase in Group 3. The activities of liver CAT and XO in Group 2 were higher than that in Group 3. LA supplementation elevated the pH_24 h and decreased drip loss in breast meat in Groups 3 and 4.

5. In conclusion, LA supplementation can improve growth performance, antioxidant properties and meat quality in broiler chicken. LA supplementation in the starter period can improve growth performance and supplementation in the grower – and in the whole period can improve carcass characteristics. There was no significant difference in meat quality of broiler chickens fed on LA-supplemented diet in different stages.