Effects of different sources and levels of dietary chromium supplementation on performance of broiler chicks

The current experiment was carried out to evaluate the effect of different dietary chromium supplementation sources, chromium oxide (Cr₂O₃), chromium methionine (Cr‐Met), or chromium yeast (Cr‐yeast), at different levels each (500 or 1,000 ppb) on growth performance, physiological traits, and carcass characteristics of broiler chicks. A total of 490 seven‐day‐old Arbor Acres chicks were randomly distributed into 7 experimental groups each in 10 replicates of 7 birds each. The groups were control, 500 ppb Cr₂O₃, 1,000 ppb Cr₂O₃, 500 ppb Cr‐Met, 1,000 ppb Cr‐Met, 500 ppb Cr‐yeast, and 1,000 ppb Cr‐yeast. The results showed significant superiority of the organic chromium sources (Cr‐Met or Cr‐yeast) concerning body weight and weight gain, the group supplemented with 1,000 ppb Cr‐yeast consumed the lowest feed (3,185 g) and had the best feed conversion ratio (1.60) compared to the control (1.73). The chromium treatments recorded significantly better protein and lipid profile, antioxidant status, and immunological parameters than the control group. Similarly, dietary chromium supplementation increased carcass yield and decreased intestinal pathogenic bacteria. In conclusion, supplementing broiler diets with organic chromium sources at 1,000 ppb promotes growth performance, physiological traits, and carcass characteristics; such chromium treatments enhanced the antioxidant status and immunity levels of broilers.     

The effect of flavour on the growth and feed utilisation of broiler chicks

The results of four experiments testing the effect of a flavour made up of ethyl butyrate and other esters, phenylacetic acid and other organic acids, oil of juniper and other essential oils, diacetyl, and maltol on the feed utilisation and growth of broiler chicks to 8 weeks of age have shown small but consistent improvements in feed conversion. This improvement was significant (P>0.05) when the 8‐week results of the four tests were pooled, but were not significant when tested within each experiment. The 4‐week results of the combined experiments indicated a highly significant (P<0.01) improvement in feed utilisation following the use of the flavour.     

The effect of different dietary levels of maize germ meal on the performance of broiler chickens

In the first experiment chicks were given pelleted diets containing 0, 10, 25 or 50% maize germ meal from 1 day of age for 4 weeks; from 4 to 8 weeks of age the birds were given a common finisher diet. In the second experiment the maize germ meal was used in broiler finisher diets at levels of 0, 10, 20 or 30%. In the third experiment, the maize germ was incorporated in diets for the entire 8‐week period. It involved three levels of the maize germ (0, 10 or 20%) in the diets given during the rearing period and four levels (0, 10, 20 or 30 %) in the diets given from 4 to 8 weeks, the experiment having a 3 x 4 factorial design.

It is concluded that maize germ meal can successfully be included in broiler diets at levels up to 20% during the first 4 weeks and up to 30 % during the second 4 weeks.     

The effect of dietary lysine level, restriction of food intake and sampling time on the levels of amino acids in the blood plasma of chicks

A suitable procedure for obtaining blood samples was established from an investigation of (a) diurnal variations in plasma amino acid concentrations and (b) the effect of controlling food intake on plasma amino acid levels.

Restriction of feeding to a 40‐min period, 105 min before sampling, significantly increased total plasma amino acid levels (P< 0.05) and individual concentrations of serine and proline (P<0.05) and glycine (P<0.01). The cause of these changes is not clear. Amino acid concentrations in samples taken at different times during the day were fairly constant. In the sampling procedure adopted routinely, birds were allowed free access to their diets for two weeks and sampled at 14.00 h on day 14.

The effect of dietary lysine level, at two protein concentrations, on plasma amino acid levels was evaluated. With inadequate and excessive dietary lysine concentrations total plasma amino acid levels were generally elevated. Plasma levels were least with diets containing 0.9 to 1.15% lysine.

The lysine requirements for optimum performance measured by growth rate, food conversion efficiency and nitrogen retention were identified as 1.2% with a 21% protein diet and approximately o‐8% with a 16% protein diet. The data indicate that efficient utilisation of dietary protein and relatively low levels of amino acids in the plasma are fairly closely related.     

半胱胺对AA肉用仔鸡生长性能的影响

选用刚出壳的AA肉鸡540只，公母各半，随机分为5组，每组设3个重复，每个重复36羽肉鸡，第1组（对照组）饲喂基础日粮，第，2，3，4组分别在基础日粮中添加60，90，120，150mg/kg的半胱胺（CS），试验结果表明：0－21日龄时，添加60mg/kg半胱胺组的平均日增重（ADG）比对照组提高5．03％（P＜0．05），22－42日龄时，添加90mg/kg CS组的ADG比对照组提高7．82％（P＜0．05），全期（0－42日龄）添加90mg/kg CS组的ADG比对照组提高5．93％（P＜0．05），添加150mg/kg CS组的ADG明显低于其它各组，添加150mg/kg CS组的料重比和成活率均明显低于其它各组，其它各组之间料重比和成率均无显著差异。     

Effect of some antibiotics as growth promoters on performance of broiler chicks fed different protein levels

This work was carried out to study the effect of different sources of dietary antibiotics (Zinc bacitracin, Flavomycin, Virginiamycin) in rations with optimal protein levels (starter phase: 23.5%, finisher phase: 20.0%) and low protein levels (starter phase: 19.6%, finisher phase: 17.0%) on broiler performance with 8 groups of 75 broiler each. The supplement of diets, containing the optimal and low protein level, with antibiotics increased the body weight after 7 weeks of age and improved the feed conversion as compared with control groups. Virginiamycin was superior in increasing body weights after 7 weeks of age and in improving the feed conversion with rations containing low protein level when compared with zinc bacitracin and Flavomycin. When broiler rations, low in the protein content, were supplemented with antibiotics, they could not substitute the difference in optimal protein level. Antibiotics supplementation increased the value of improvement in production efficiency and this was more pronounced with Virginiamycin.     

维生素A对AA肉鸡生长发育和肝肾功能的影响

1周龄AA肉鸡150只,随机分为A、B、C、D、E、F 6组,每组25只,自由采食以玉米、豆饼为主的基础日粮,日粮中分别添加维生素A 0、4500、9000、37500、150000和450000 IU/kg,在不同日龄检测肉鸡体重、脏器系数和肝肾功能等指标.结果表明:①维生素A缺乏可引起肉鸡生长速度下降,增重缓慢,造成肉鸡脾脏系数(后期)和法氏囊系数(前期)降低;高剂量维生素A(F组)前期显著降低睾丸系数,后期显著降低肉鸡的增重和法氏囊系数,增加肉鸡心脏系数、肾脏系数和胸腺系数.②高剂量维生素A(F组)后期显著降低肉鸡血清白蛋白和尿酸的含量,升高血清谷草转氨酶(GOT)活性、球蛋白的含量,影响其肝肾功能.     

Potential of chemical regulation of food intake and body weight of broiler breeder chicks

1. Two experiments were performed to evaluate the potential of phenylpropanolamine hydrochloride and monensin sodium as appetite- and weight-control agents for Indian River broiler breeder chicks. 2. In experiment 1, a total of 300 day-old sexed broiler breeder chicks were individually weighed and placed in battery cages. They were randomly assigned to 5 dietary treatments, namely 0, 50, 100, 200 and 400 mg/kg of phenylpropanolamine hydrochloride added to a maize-soyabean meal basal diet. 3. In experiment 2, a total of 400 day-old sexed broiler breeder chicks were randomly assigned to 10 dietary treatments which were a combination of two concentrations of dietary crude protein (200 and 150 g/kg) and 5 different concentrations of added drugs in the diet, namely 0, 500 and 800 mg/kg of phenylpropanolamine hydrochloride and 200 and 300 mg/kg of monensin sodium. 4. Food consumption and body weight gain were significantly reduced by feeding diets containing the drugs but mortality was not significantly affected. Birds showed evidence of increased tolerance, with age, to phenylpropanolamine but not to monensin. 5. Monensin sodium, at high inclusion rates, was found to be a more potent and effective appetite- and growth-depressing agent for broiler breeder chicks than phenylpropanolamine and may have application in broiler breeder production using an ad libitum feeding programme.     

Metabolic and economic efficiency of broiler chicks as affected by dietary protein levels.

1. An experiment was designed to determine if decreasing excess amino acids in the diets of chicks would improve metabolic efficiency, as indicated by growth rate and food efficiency. 2. Semi-purified diets were fed with crude protein contents of 180 or 230 g/kg. The sources of protein were maize gluten meal, groundnut meal, sesame meal or soya-bean meal. Crystalline amino acids were supplemented to meet all amino acid requirements. 3. The dietary crude protein content had no statistically significant effect on weight gain or food consumption. The probability that the higher protein improved gain per food was 0.06. Protein source had a significant effect on all the responses measured. 4. Decreased concentrations of excess amino acids in chick diets had no favourable effects on weight gain or gain per food. Lower protein diets were more expensive per unit of gain.     

不同蛋白质水平日粮对云南武定鸡生长性能及血液生化指标的影响

选用192只平均体重接近的云南武定鸡,随机分为3组,分别饲喂3种不同的蛋白质水平(17.50%、18.00%和19.50%)日粮,探讨日粮蛋白质水平对30～60日龄云南武定鸡生长性能及血液生化指标的影响.试验结果表明提高日粮蛋白质水平可以提高日增重和降低料重比,改善生长性能,但差异不明显(P＞0.05),对血液生化指标中的瘦素、T3和胆固醇含量有显著影响(P＜0.05),对其他各项血液生化指标均无显著影响(P＞0.05).     

Effects of dietary sorghum of different tannin concentrations and tallow supplementation on the performance of broiler chicks

1. The chemical compositions and tannin contents of 17 varieties of grain sorghum were determined.

2. Commercial broiler chicks were fed from 7 to 49 d of age on 15 experimental diets which varied in their concentrations of tannins and animal fat (tallow), by the inclusion of different amounts of high and a low protein varieties of sorghum.

3. Substitution of a low tannin sorghum completely for maize did not have any significantly adverse effect on performance. Broiler chicks could tolerate up to 2.6 g tannin/kg above which their performance was reduced. Addition of tallow did not significantly affect broiler performance except at the highest tannin content and added fat intake, where weight gain and efficiency appeared to improve significantly.     

The quantification of the effect of increasing levels of various fats on body weight gain, efficiency of food conversion and food intake of growing chicks

A study, based on data from the literature, was carried out to establish the quantitative effect of increasing levels of various fats on food intake, weight gain and efficiency of food conversion of growing chicks.

The fats concerned were soyabean oil, soyabean soapstock, maize oil, lard, grease and tallow. Their effect was studied by using regression analyses.

It was found that the addition of fat, both animal fats and vegetable oils, diminishes food intake. The food intake decreases significantly with rising percentages of fat according to a linear function. No differences in effect between various fats could be demonstrated.

The incorporation of various fats improves the weight gain, although the increase was not related to the amount of fat added. The improvement in weight gain differs from one fat to an other.

The addition of fats improves efficiency of food conversion, but varies according to the kind of fat. Here the improvement is correlated with the level of fat added.

The difference in improvement of food conversion can be only partially explained by differences in absorbability and metabolisable energy of the fats.

It is concluded that certain fats ameliorate the efficiency of food conversion and, in some cases, weight gain to a higher degree as may be expected from their metabolisable energy content. It might be possible that some fats possess one or more factors which improve the efficiency of metabolisable energy or exert a protein anabolic action.     

Effects of different sulphur amino acids and dietary electrolyte balance levels on performance,jejunal morphology,and immunocompetence of broiler chicks

As alterations of dietary electrolyte balance (DEB) can influence amino acid metabolism via changes the ions incur in their configurations, performance and immunological responses of broiler chicks might be affected. So, the current study was carried out to investigate the effects of different levels of sulphur amino acids (SAA) and DEB on performance, jejunal morphology and immunocompetence of broiler chicks. A total of 360 1‐day‐old male Ross 308 broiler chicks were randomly assigned to nine experimental treatments with four replicates of 10 birds each. Experimental treatments consisted of three levels of SAA (100, 110, and 120% of NRC recommendation, provided by methionine supplementation in diets with the same cysteine level) and three levels of DEB (150, 250, and 350 mEq/kg) that were fed during the entire of trial in a 3 × 3 factorial arrangement. Results showed that the relative weights of intestine and abdominal fat were decreased markedly (p < 0.001) with increasing levels of SAA and DEB respectively. Antibody titre against sheep red blood cell was neither individually nor in combination influenced by supplementation of SAA or DEB. Nevertheless, a decrease in DEB level led to a suppression in heterophile (p < 0.05) and an increase in lymphocyte counts (p = 0.06); consequently, heterophile to lymphocyte ratio was significantly decreased (p < 0.05) by decremental levels of DEB. Albumin to globulin ratio was increased after inclusion of at least 10% SAA (p < 0.001) and 150 mEq DEB/kg in the diet (p = 0.11). Although feeding high‐DEB level led to a remarkable decrease in villus height (p < 0.01) and goblet cell numbers (p < 0.001), supplementing the highest level of SAA improved the height of jejunal villus. During the entire trial period, average daily feed intake (ADFI) was increased by incremental SAA levels (p < 0.05). However, inclusion of 150 mEq/kg led to not only a remarkable increase (p < 0.0001) in both ADFI and average daily weight gain (ADWG) but also to improved (p < 0.001) feed conversion ratio (FCR) both during the growing and over the entire trial periods. The present findings indicated that inclusion of low DEB decreased the heterophile to lymphocyte ratio and improved both the albumin to globulin ratio and intestinal health indices. The best growth performance was obtained with 150 mEq DEB/kg in the diet for each level of SAA.     

The dietary effect of different wheat cultivars for broiler chickens.

1. An experiment was conducted to examine the variability in chemical composition of 16 wheat cultivars and to study how this variability affected the performance of broiler chickens given diets containing 650 or 815 g wheat/kg diet during the first 3 weeks of life. Intestinal viscosity, apparent fat digestibility and apparent metabolisable energy were determined with all diets. Intestinal pH and the relative weight of different parts of the intestine were measured in chickens fed on diets with the high wheat inclusion. 2. The 16 wheat cultivars varied in chemical composition, with protein content ranging from 112 to 127 g/kg dry matter, starch content from 658 to 722 g/kg dry matter and non-starch polysaccharides from 98 to 117 g/kg dry matter. The effect of the different wheat cultivars on the measured parameters was most pronounced in chickens fed on diets with 815 g wheat/kg diet (P<0.001). However, significant (P<0.001) differences between cultivars were still present at the lower wheat content. 3. Milling-quality wheats resulted in better performance (P<0.001) than feeding-quality wheats at the high inclusion, whereas such an effect could not be registered in diets at the lower wheat inclusion. These results indicate that some of the feeding wheats are comparable in quality to milling wheats when included at the concentrations which are more common in practical broiler diets. 4. Decreasing the wheat content in the diets resulted in significantly (P<0.001) better performance and considerably (P<0.001) lower intestinal viscosity (jejunum; 2.4 to 5.9 cps, ileum; 4.6 to 10.9 cps) than in chickens fed on diets with the higher wheat inclusion level (jejunum; 9.1 to 38.4 cps, ileum; 20.8 to 82.0 cps). 5. Diets with 815 g wheat/kg influenced pH in the caeca, but not in the ileum and gizzard. The relative weights of the gizzard and ileum differed significantly (P<0.05) between treatments, whereas those of duodenum, jejunum and caeca were not affected by dietary addition of the different wheat cultivars. 6. The present study demonstrated that the chemical composition and the nutritive value of Danish wheats for broilers vary markedly. The results indicated that the non-starch polysaccharide and especially the arabinoxylan content of wheat are important factors in the discussion of the result obtained. Poor correlations were seen between performance and AMEn and care should be taken when using AMEn values alone to predict the nutritive value of wheat and wheat-based diets.     

酵母细胞壁在白羽肉鸡生长性能及免疫功能方面的效应

为了研究酵母细胞壁对白羽肉鸡生长性能指标以及新城疫抗体水平的影响,试验选用1日龄科宝肉鸡432羽,随机分为6个处理组,每个处理组6个重复,每个重复12羽。对照组A饲喂基础日粮,B组饲喂含金霉素(50 mg/kg)的基础日粮,C、D、E、F组饲喂添加不同含量(0.5、1、2、10 kg/t)的酵母细胞壁的基础日粮。结果表明:日粮中添加酵母细胞壁能提高肉鸡的生长性能,出栏体重较对照组分别提高6.16%、9.45%、5.09%、1.09%;同时酵母细胞壁可提高肉鸡的新城疫抗体水平和免疫器官指数,增强肉鸡免疫水平。在本试验条件下,添加1 kg/t酵母细胞壁,增重及抗体水平最高。     

Pathology and histology of dietary tryptophan deficiency in broiler chicks

The purpose of this experiment was to characterize a lesion of the rhamphotheca associated with tryptophan (TIRP) deficiency, search for other histological abnormalities,and determine whether bird size and housing conditions are contributing factors to these lesions. Day-old broiler chicks (Ross X Ross 308) were placed in either floor pens with fresh pine shavings or Petersime battery brooders with two pens of 10 chicks each per treatment. Broiler chicks from 0 to 21 days of age were fed adequate (0.24%) and deficient (0.09%) levels of TRP in diets based on corn, corn gluten meal, and gelatin. Separate groups of control chicks were pair fed daily with the deficient chicks. Deficient chicks grew less efficiently than did the pair-fed controls. Upon gross examination, a lesion of the maxillary rhamphotheca in the vicinity of the nares was observed in 61% of TRP-deficient birds housed in the battery and 13% of the birds housed in floor pens. A similar gross lesion was only observed in one control bird. These lesions were located along the upper portion of the beak between the nares and appeared as a crusty or scab-like area on gross examination, composed of detritus, heterophils, and plasma protein. Inflammation occasionally was observed at the dermoepidermal junction. The incidence of lesions was reduced in floor pens compared to battery brooders, but similarly sized birds did not exhibit the lesion. The number of lesions seen grossly and histologically in TRP-deficient birds, as compared to control birds, supports the hypothesis that TRP deficiency is the primary cause of these lesions around the nares of broilers. Secondary environmental factors, perhaps coprophagy, also influence the incidence of the lesion.     

Early growth and environmental implications of dietary zinc and copper concentrations and sources of broiler chicks

1. Environmental accumulation of zinc and copper is becoming a concern in areas having intensive animal production. This study examined performance and excretion of broiler chicks given diets supplemented with graded concentrations of zinc and copper from three different sources. 2. Two experiments were conducted, each utilising 570 1-d-old chicks. In Experiment 1, chicks were given diets containing supplemental zinc concentrations from 40 to 120 mg/kg supplied as zinc sulphate, a zinc amino acid complex (Availa Zn), or a combination of zinc sulphate and Availa Zn with each contributing one-half of the total supplemental zinc. In Experiment 2, broiler chicks were given diets with graded concentrations of supplemental copper ranging from 4 to 12 mg/kg from copper sulphate, a copper amino acid complex (Availa Cu), or a combination of copper sulphate and Availa Cu with each contributing one-half of the total supplemental copper. 3. During the 17-d experimental period, mineral concentration or source did not influence body weight, feed conversion, or the incidence of mortality from 1 to 17 d. 4. Decreasing dietary zinc concentration from 120 to 40 mg/kg reduced zinc excretion by 50%. 5. Copper excretion was decreased by 35% as supplemental copper was reduced from 12 to 4 mg/kg. 6. Reducing dietary zinc and copper concentrations can potentially decrease the accumulation of heavy metals in the environment without compromising bird performance.     

维生素C、E及其交互作用对肉仔鸡生长性能及鸡肉品质的影响

本试验旨在研究维生素C、E(VC、VE)及其交互作用对肉仔鸡生长及其鸡肉品质的影响。试验采用4×4完全随机试验设计将800只1日龄健康的艾维茵肉仔鸡随机分成16个处理,每个处理5个重复,每个重复10只。其中,VE设4个添加水平,分别为50、100、200、400 mg/kg日粮,VC的添加水平为50、100、200、400 mg/kg日粮。结果表明:在生长前期(0～21 d),日粮VE、VC的添加量对肉仔鸡日增重均无显著影响(P>0.05),VE、VC的互作效应在生长前期对肉仔鸡日增重和料重比的影响均不显著(P>0.05),前期VE(200 mg/kg)×VC(50 mg/kg)组料重比最低;在生长后期(4～6周龄),日粮VE、VC的添加量对肉仔鸡日增重、料重比的影响均显著(P<0.05),VE、VC的互作效应对肉仔鸡生长后期日增重和料重比的影响均显著(P<0.05);不同的VE、VC处理组之间pH 45 min、pH 12h、pH 24 h值、肉色、肌间脂肪、最大剪切力的差异均不显著(P>0.05),且VE、VC之间无显著的互作效应(P>0.05);不同维生素E组之间的滴水损失率差异极显著(P<0.01),...